vldb_check: cope with broken names and volids

Fix-up broken vlentry names and rw volid so entries can be looked
up in the vlserver and can be deleted with vos delentry if needed.

Change-Id: Ide4855b0ef149977b04e3f0b5c966b13dd1cf417
Reviewed-on: http://gerrit.openafs.org/9905
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
vldb_check: print vlentry file offsets

To aid in debugging, consistently print the vlentry database "address"
and the file offset when displaying errors for vlentries.  Print the
vlentry file offsets when printing all the entries with the -entries
option.

Change-Id: I3ef37e6654280f0cff9b2449da29aebe7c5e3aad
Reviewed-on: http://gerrit.openafs.org/9906
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>