recognizes :openstack_auth_token, :openstack_management_url, :persistent,
                   :openstack_service_type, :openstack_service_name, :openstack_tenant,
                   :openstack_endpoint_type, :openstack_region, :openstack_domain_id,
                   :openstack_project_name, :openstack_domain_name,
                   :openstack_user_domain, :openstack_project_domain,