Fix enable on boot when working with systemd and symlinked units

mysql on Fedora20 is actually mariadb and /usr/lib/systemd/system/mysqld.service
is a symbolic link to /usr/lib/systemd/system/mariadb.service. systemctl "enable"
doesn't work on symlinked inits like described in:

https://bugzilla.redhat.com/1014311

So in order to enable mysqld service properly in this case we need to
replace a service name with the real path to service file.

Closes-Bug: #1330937
Change-Id: Id823b3e377c4d0d5f1e5452fad9826232bc1f904
Fix typos in trove/instance/models.py

Change-Id: Ied4da362562d89fd6d2295ad64b560ba5d950b42
Closes-Bug: #1333894
Fix data too long for column 'task_description'

Change-Id: I9153cc1a8a194990b3b437fcab0ceddbd716e247
Closes-Bug: #1334360
Updated from global requirements

Change-Id: I9656ca53d9f638f3d3091ba60144a450279d7b81
Merge "Fix data too long for column 'task_description'"
Merge "Fix enable on boot when working with systemd and symlinked units"
Merge "Fix typos in trove/instance/models.py"
Merge "Updated from global requirements"
Update backup state when guest error occures

Reason:
  - When guest error appears at 'create_backup'
    stage, backup still remain in NEW state.

Changes:
  - updating status when guest error appears;
  - updating backup model with a new method;
  - adding test;

Change-Id: I05f5caea4380edbe0e8bebc618ecfb52afe45872
Closes-Bug: #1333659
Mark all running backups as FAILED when instance was deleted

Reasons:
 - users are able to delete instance while it's in BACKUP state
   and all running backups are hanging in NEW state
   and cannot be deleted;

Changes:
 - when `instance-delete` action called, all running backup
   are being marked as FAILED;
 - int-tests proposed.

Change-Id: I53d13eaa81d368864c0a278c557c7f11a509e3ea
Closes-Bug: #1220989