Fix Keystone response for testing to not include Glance version

This changes the Keystone catalog response used for testing to only include the base Glance endpoint, since clients should be performing version negotiation with Glance.

Please see this ticket: https://issues.apache.org/jira/browse/JCLOUDS-494

As well as this PR: https://github.com/jclouds/jclouds-labs-openstack/pull/82