Exception when trying to back up: ValueError: invalid literal for int() (lp:#1313413)

[Original report](https://bugs.launchpad.net/bugs/1313413) created by **Dmitry (shintyakov)**
```
Duplicity version: 0.6.23
Python version: 2.7.6
System: arch linux
Previously I successfully backed up my system with duplicity, but now
attampt to launch gives mw stack trace with exception:



Last lines of the log:

Added incremental Backupset (start_time: Sun Sep 23 18:13:44 2012 /
end_time: Sun Sep 30 21:37:16 2012)
Added set Sun Sep 30 21:37:16 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sun Sep 30 21:37:16 2012]
Added incremental Backupset (start_time: Sun Sep 30 21:37:16 2012 /
end_time: Sat Oct 20 13:43:12 2012)
Added set Sat Oct 20 13:43:12 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Oct 20 13:43:12 2012]
Added incremental Backupset (start_time: Sat Oct 20 13:43:12 2012 /
end_time: Sat Oct 27 15:23:55 2012)
Added set Sat Oct 27 15:23:55 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Oct 27 15:23:55 2012]
Added incremental Backupset (start_time: Sat Oct 27 15:23:55 2012 /
end_time: Mon Nov  5 13:20:41 2012)
Added set Mon Nov  5 13:20:41 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Mon Nov  5 13:20:41 2012]
Added incremental Backupset (start_time: Mon Nov  5 13:20:41 2012 /
end_time: Sat Nov 10 23:52:07 2012)
Added set Sat Nov 10 23:52:07 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Nov 10 23:52:07 2012]
Added incremental Backupset (start_time: Sat Nov 10 23:52:07 2012 /
end_time: Sat Nov 17 21:15:40 2012)
Added set Sat Nov 17 21:15:40 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Nov 17 21:15:40 2012]
Added incremental Backupset (start_time: Sat Nov 17 21:15:40 2012 /
end_time: Sat Dec  1 20:38:29 2012)
Added set Sat Dec  1 20:38:29 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Dec  1 20:38:29 2012]
Added incremental Backupset (start_time: Sat Dec  1 20:38:29 2012 /
end_time: Fri Dec 14 23:36:22 2012)
Added set Fri Dec 14 23:36:22 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Fri Dec 14 23:36:22 2012]
Added incremental Backupset (start_time: Fri Dec 14 23:36:22 2012 /
end_time: Thu Dec 27 23:44:18 2012)
Added set Thu Dec 27 23:44:18 2012 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Thu Dec 27 23:44:18 2012]
Added incremental Backupset (start_time: Thu Dec 27 23:44:18 2012 /
end_time: Sat Jan  5 13:58:17 2013)
Added set Sat Jan  5 13:58:17 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Jan  5 13:58:17 2013]
Added incremental Backupset (start_time: Sat Jan  5 13:58:17 2013 /
end_time: Sun Jan 27 01:36:32 2013)
Added set Sun Jan 27 01:36:32 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sun Jan 27 01:36:32 2013]
Added incremental Backupset (start_time: Sun Jan 27 01:36:32 2013 /
end_time: Wed Feb 13 21:41:00 2013)
Added set Wed Feb 13 21:41:00 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Wed Feb 13 21:41:00 2013]
Added incremental Backupset (start_time: Wed Feb 13 21:41:00 2013 /
end_time: Tue Mar  5 00:01:58 2013)
Added set Tue Mar  5 00:01:58 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Tue Mar  5 00:01:58 2013]
Added incremental Backupset (start_time: Tue Mar  5 00:01:58 2013 /
end_time: Sat Mar 16 22:07:06 2013)
Added set Sat Mar 16 22:07:06 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Mar 16 22:07:06 2013]
Added incremental Backupset (start_time: Sat Mar 16 22:07:06 2013 /
end_time: Sat Mar 23 21:58:49 2013)
Added set Sat Mar 23 21:58:49 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Mar 23 21:58:49 2013]
Added incremental Backupset (start_time: Sat Mar 23 21:58:49 2013 /
end_time: Sun Mar 31 11:44:40 2013)
Added set Sun Mar 31 11:44:40 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sun Mar 31 11:44:40 2013]
Added incremental Backupset (start_time: Sun Mar 31 11:44:40 2013 /
end_time: Sat Apr 20 23:22:58 2013)
Added set Sat Apr 20 23:22:58 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Apr 20 23:22:58 2013]
Added incremental Backupset (start_time: Sat Apr 20 23:22:58 2013 /
end_time: Tue Apr 30 23:03:56 2013)
Added set Tue Apr 30 23:03:56 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Tue Apr 30 23:03:56 2013]
Added incremental Backupset (start_time: Tue Apr 30 23:03:56 2013 /
end_time: Sun May 26 17:01:08 2013)
Added set Sun May 26 17:01:08 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sun May 26 17:01:08 2013]
Added incremental Backupset (start_time: Sun May 26 17:01:08 2013 /
end_time: Sat Jun  8 23:25:14 2013)
Added set Sat Jun  8 23:25:14 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sat Jun  8 23:25:14 2013]
Added incremental Backupset (start_time: Sat Jun  8 23:25:14 2013 /
end_time: Sun Jun 23 20:52:14 2013)
Added set Sun Jun 23 20:52:14 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Sun Jun 23 20:52:14 2013]
Added incremental Backupset (start_time: Sun Jun 23 20:52:14 2013 /
end_time: Fri Jul 12 22:48:15 2013)
Added set Fri Jul 12 22:48:15 2013 to pre-existing chain [Sun Feb 19
18:23:59 2012]-[Fri Jul 12 22:48:15 2013]
Found backup chain [Mon Oct 14 23:36:31 2013]-[Mon Oct 14 23:36:31 2013]
Ignoring incremental Backupset (start_time: Mon Oct 14 23:36:31 2013;
needed: Fri Jul 12 22:48:15 2013)
Added incremental Backupset (start_time: Mon Oct 14 23:36:31 2013 /
end_time: Sat Dec 28 22:03:53 2013)
Added set Sat Dec 28 22:03:53 2013 to pre-existing chain [Mon Oct 14
23:36:31 2013]-[Sat Dec 28 22:03:53 2013]
Ignoring incremental Backupset (start_time: Sat Dec 28 22:03:53 2013;
needed: Fri Jul 12 22:48:15 2013)
Added incremental Backupset (start_time: Sat Dec 28 22:03:53 2013 /
end_time: Sat Jan 11 19:02:38 2014)
Added set Sat Jan 11 19:02:38 2014 to pre-existing chain [Mon Oct 14
23:36:31 2013]-[Sat Jan 11 19:02:38 2014]
Ignoring incremental Backupset (start_time: Sat Jan 11 19:02:38 2014;
needed: Fri Jul 12 22:48:15 2013)
Added incremental Backupset (start_time: Sat Jan 11 19:02:38 2014 /
end_time: Sat Feb  8 16:13:20 2014)
Added set Sat Feb  8 16:13:20 2014 to pre-existing chain [Mon Oct 14
23:36:31 2013]-[Sat Feb  8 16:13:20 2014]
Found backup chain [Sat Feb 15 12:34:57 2014]-[Sat Feb 15 12:34:57 2014]
Last full backup date: Sat Feb 15 12:34:57 2014
Collection Status
-----------------
Connecting with backend: LocalBackend
Archive dir: /home/myname/.cache/duplicity/c3e6120fe7300af2676b1800e9af401f

Found 2 secondary backup chains.
Secondary chain 1 of 2:
-------------------------
Chain start time: Sun Feb 19 18:23:59 2012
Chain end time: Fri Jul 12 22:48:15 2013
Number of contained backup sets: 33
Total number of contained volumes: 1249
 Type of backup set:                            Time:      Num volumes:
                Full         Sun Feb 19 18:23:59 2012               527
         Incremental         Sun Feb 19 20:11:05 2012                 1
         Incremental         Thu Mar  8 18:18:57 2012                11
         Incremental         Sat May 12 23:15:20 2012                10
         Incremental         Sun May 27 16:02:41 2012                 1
         Incremental         Tue Jun 12 16:39:22 2012                 1
         Incremental         Sun Aug  5 15:22:21 2012                36
         Incremental         Sat Aug 11 20:26:06 2012                 1
         Incremental         Sun Aug 26 02:22:03 2012                15
         Incremental         Thu Sep  6 23:52:09 2012                 7
         Incremental         Sun Sep 23 18:13:44 2012                59
         Incremental         Sun Sep 30 21:37:16 2012                17
         Incremental         Sat Oct 20 13:43:12 2012                 4
         Incremental         Sat Oct 27 15:23:55 2012                 1
         Incremental         Mon Nov  5 13:20:41 2012                95
         Incremental         Sat Nov 10 23:52:07 2012                 8
         Incremental         Sat Nov 17 21:15:40 2012                33
         Incremental         Sat Dec  1 20:38:29 2012                26
         Incremental         Fri Dec 14 23:36:22 2012               104
         Incremental         Thu Dec 27 23:44:18 2012                 1
         Incremental         Sat Jan  5 13:58:17 2013                 2
         Incremental         Sun Jan 27 01:36:32 2013               133
         Incremental         Wed Feb 13 21:41:00 2013                 1
         Incremental         Tue Mar  5 00:01:58 2013                 2
         Incremental         Sat Mar 16 22:07:06 2013                 3
         Incremental         Sat Mar 23 21:58:49 2013                 2
         Incremental         Sun Mar 31 11:44:40 2013                 1
         Incremental         Sat Apr 20 23:22:58 2013                 3
         Incremental         Tue Apr 30 23:03:56 2013               134
         Incremental         Sun May 26 17:01:08 2013                 5
         Incremental         Sat Jun  8 23:25:14 2013                 2
         Incremental         Sun Jun 23 20:52:14 2013                 1
         Incremental         Fri Jul 12 22:48:15 2013                 2
-------------------------

Secondary chain 2 of 2:
-------------------------
Chain start time: Mon Oct 14 23:36:31 2013
Chain end time: Sat Feb  8 16:13:20 2014
Number of contained backup sets: 4
Total number of contained volumes: 749
 Type of backup set:                            Time:      Num volumes:
                Full         Mon Oct 14 23:36:31 2013               716
         Incremental         Sat Dec 28 22:03:53 2013                28
         Incremental         Sat Jan 11 19:02:38 2014                 3
         Incremental         Sat Feb  8 16:13:20 2014                 2
-------------------------


Found primary backup chain with matching signature chain:
-------------------------
Chain start time: Sat Feb 15 12:34:57 2014
Chain end time: Sat Feb 15 12:34:57 2014
Number of contained backup sets: 1
Total number of contained volumes: 702
 Type of backup set:                            Time:      Num volumes:
                Full         Sat Feb 15 12:34:57 2014               702
-------------------------
No orphaned or incomplete backup sets found.
PASSPHRASE variable not set, asking user.
GnuPG passphrase:
PASSPHRASE variable not set, asking user.
Retype passphrase to confirm:
PASSPHRASE variable not set, asking user.
Registering (mktemp) temporary file /tmp/duplicity-aAlEHC-
tempdir/mktemp-J5v_9q-2
Deleting /tmp/duplicity-aAlEHC-tempdir/mktemp-J5v_9q-2
Forgetting temporary file /tmp/duplicity-aAlEHC-tempdir/mktemp-J5v_9q-2
Releasing lockfile <lockfile.linklockfile.LinkLockFile instance at
0x9c4260c>
Removing still remembered temporary file /tmp/duplicity-aAlEHC-
tempdir/mkstemp-f_Fx10-1
Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1493, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1487, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1336, in main
    do_backup(action)
  File "/usr/bin/duplicity", line 1468, in do_backup
    check_last_manifest(col_stats) # not needed for full backup
  File "/usr/bin/duplicity", line 1169, in check_last_manifest
    last_backup_set.check_manifests()
  File "/usr/lib/python2.7/site-packages/duplicity/collections.py", line
190, in check_manifests
    remote_manifest = self.get_remote_manifest()
  File "/usr/lib/python2.7/site-packages/duplicity/collections.py", line
232, in get_remote_manifest
    return manifest.Manifest().from_string(manifest_buffer)
  File "/usr/lib/python2.7/site-packages/duplicity/manifest.py", line 186,
in from_string
    vi = VolumeInfo().from_string(match.group(2))
  File "/usr/lib/python2.7/site-packages/duplicity/manifest.py", line 377,
in from_string
    self.end_block = int(other_fields[1])
ValueError: invalid literal for int() with base 10: '10Volume'


Command line, used to run duplicity:
duplicity --full-if-older-than 4M --allow-source-mismatch\
    ... some include/exclude directives....
    /home/myname \
    file:///mnt/nfs/mybook/Backups/Home
```

Story points: 6.0