Add wait until nailgun will be operable to rollback tests

-In case of rollback some services need time to start
so we need to wait in tests for these services to start

Change-Id: I34ae6388fe023cad929c1c039d4f7643658548be
Closes-Bug: #1392393
Merge "Add wait until nailgun will be operable to rollback tests" into stable/5.1