Add RBAC test for 'get_auth_domains'

Adding 'get_auth_domains' rbac test for this policy[1]
[1]https://github.com/openstack/keystone/blob/master/keystone/common/policies/auth.py#L50

Change-Id: I0da9330a455dabe5c21b0a6d35bc5bb1ba6cd875
1 file changed