default service_type atribute in url_for method should be 'identity'

[Paulo Ewerton]

url_for method in class ServiceCatalog sets None as default value for service_type. This raises an EndpointNotFound exception every time the method is called if no service_type is explicitly set by the caller. Refer to: https://github.com/openstack/keystoneauth/blob/master/keystoneauth1/service_catalog.py#L133

service_type default value should then be set to 'identity', reflecting the url_for method version defined in keystoneclient: https://github.com/openstack/python-keystoneclient/blob/feature/keystoneauth_integration/keystoneclient/service_catalog.py#L195.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/204253

[OpenStack Infra (hudson-openstack)]

Change abandoned by Paulo Ewerton Gomes Fragoso (<email address hidden>) on branch: master
Review: https://review.openstack.org/204253
Reason: Abandoned in favor of: https://review.openstack.org/#/c/210268/

[Morgan Fainberg (mdrnstm)]

Change was abandoned and the referenced patch has been included in the 1.0.0 release