Manila CI hooks for DHSS=False job with the Generic driver wait for
service instance availability and right after it becomes available
returns control to caller. And caller can run tests with creation of
shares immediately. But, in this case, we can face race conditions when
manila-share service requires some time to inform manila-scheduler.
So, add 'sleep 10' operation to be executed after reaching 'available'
state by service instance.It should be enough to overcome races.
Change-Id: Ie4ae231701edaab319c9012e476d1f63e3806499