Improving domain_id update tests
Improving domain_id update tests

Improves the tests of domain_id update of groups, users and projects.
These tests did not check whether the domain_id was correctly updated,
just performed the update operation.

Related-bug: 1479452

Change-Id: I34f15298a6a5593a660bee467964be682d616efc

ajayaa/keystone,ilay09/keystone,mahak/keystone,klmitch/keystone,openstack/keystone,maestro-hybrid-cloud/keystone,mahak/keystone,rajalokan/keystone,dims/keystone,himanshu-setia/keystone,openstack/keystone,openstack/keystone,dims/keystone,klmitch/keystone,rajalokan/keystone,ilay09/keystone,rajalokan/keystone,ajayaa/keystone,cernops/keystone,cernops/keystone,maestro-hybrid-cloud/keystone,mahak/keystone,himanshu-setia/keystone,ilay09/keystone