Add Rbac test for "group_snapshot"

This PS adds Rbac test for "group_snapshot" policy[0], api-ref[1]

[0]https://github.com/openstack/cinder/blob/0cf910d4345c000e8c306b1cb2b2dd291975cf71/cinder/policies/group_snapshots.py
[1]https://developer.openstack.org/api-ref/block-storage/v3/#delete-a-consistency-group-snapshot

Change-Id: I83d0f9c7b5e6f4e0dd7449611a11229d5d5de6ed
1 file changed