[Grenade] Add test with creation of share snapshot
[Grenade] Add test with creation of share snapshot

Extend test coverage for 'upgrade' devstack logic (grenade) by
adding new test that creates share snapshot.

Change-Id: I2610fe744123eab2b3fc6ed74ed191e38cecb92e

openstack/manila,bswartz/manila,bswartz/manila,vponomaryov/manila,vponomaryov/manila,openstack/manila