Apply six for metaclass

__metaclass__ cannot be used in python3.
six be used in general for python 3 compatibility.

Change-Id: I0d7c61b4c0103d4f9e627ff5d22cddcdff2f7274
Fix inheritance for ConfigurationParameterDeleted

Reasons:
 - ConfigurationParameterDeleted is not
   inherited from any of exception classes.

Changes:
 - inheritance was updated from object to TroveError

Change-Id: I1e476ff7547ffb8efcc7fc3a13312b0f16fc4392
Closes-Bug: #1328865
Add datastore version to backups

This fix adds datastore information to the backup APIs.
These API includes backup list, backup list by instance and
backup show.

Also this fix enhances backup-list to optionally receive a
datastore to filter the backups by.

The integration tests will fail until the update for the client
gets merged: https://review.openstack.org/#/c/90462/

Change-Id: Icfec975b92cd9523e639ad6a2d6787ee4d4cb39d
Implements: blueprint backup-metadata
Reverting deleted tests

Reasons:
 - To merge MongoDB and the mount_path patches,
   certain tests were removed.

Change-Id: Iab92f629408e9b5973449e2a5e4f2403a3ff2525
Closes-Bug: #1287371
Imported Translations from Transifex

Change-Id: I01cc796de1f7fd9b6da3e45fb172990a623ec27d
Merge "Imported Translations from Transifex"
Merge "Apply six for metaclass"
Merge "Reverting deleted tests"
Merge "Fix inheritance for ConfigurationParameterDeleted"