recognizes :openstack_auth_token, :openstack_management_url,
                   :persistent, :openstack_service_type, :openstack_service_name,
                   :openstack_tenant, :openstack_tenant_id,
                   :openstack_api_key, :openstack_username, :openstack_identity_endpoint,
                   :current_user, :current_tenant, :openstack_region,