Refresh v2 and v3 portion of policy.json from upstream keystone
repository @ commit
d4a890a6c8bd6927e229f4b665a982a51c130073

Add functional tests to verify effect of policy

Update functional tests to use keystone_configure_api_version
from charm-helpers

Update functional tests to correctly validate cinder services
when openstack release >= ocata

Enable functional test for ocata, set appropriate cinder
configuration.

Change-Id: Idf07ff3a7c9d7e7eb30792719541319ab3426a41
Closes-Bug: 1651989
Closes-Bug: 1649446