Trove navigation panel should not be plural

To be consistent with all other groups in the
dashboard navigation panel e.g. compute,
Orchestration etc rename Trove to be
Database instead of Databases

Change-Id: Ib308588e71fad1f197393a9eba18e5f4189088f1
Closes-Bug: #1336817
Merge "Trove navigation panel should not be plural"