KVS support domain as namespace for users
KVS support domain as namespace for users

The KVS identity backend didn't support having users with the
same name in different domains.

Change-Id: I4f6a9010ed085aef9cba5f368e292dd28339a0fa
Related-bug: #1265108

rushiagr/keystone,himanshu-setia/keystone,maestro-hybrid-cloud/keystone,idjaw/keystone,dsiddharth/access-keys,cernops/keystone,blueboxgroup/keystone,rajalokan/keystone,takeshineshiro/keystone,idjaw/keystone,reeshupatel/demo,rajalokan/keystone,dstanek/keystone,jonnary/keystone,jumpstarter-io/keystone,openstack/keystone,klmitch/keystone,openstack/keystone,jamielennox/keystone,rodrigods/keystone,ging/keystone,cernops/keystone,JioCloud/keystone,rushiagr/keystone,dims/keystone,jonnary/keystone,nuxeh/keystone,roopali8/keystone,maestro-hybrid-cloud/keystone,takeshineshiro/keystone,ajayaa/keystone,roopali8/keystone,UTSA-ICS/keystone-kerberos,derekchiang/keystone,klmitch/keystone,ajayaa/keystone,mahak/keystone,mahak/keystone,vivekdhayaal/keystone,nuxeh/keystone,dstanek/keystone,JioCloud/keystone,dstanek/keystone,vivekdhayaal/keystone,himanshu-setia/keystone,jumpstarter-io/keystone,rodrigods/keystone,jumpstarter-io/keystone,jamielennox/keystone,ilay09/keystone,rajalokan/keystone,promptworks/keystone,vivekdhayaal/keystone,promptworks/keystone,derekchiang/keystone,nuxeh/keystone,blueboxgroup/keystone,derekchiang/keystone,ging/keystone,reeshupatel/demo,openstack/keystone,reeshupatel/demo,dsiddharth/access-keys,UTSA-ICS/keystone-kerberos,MaheshIBM/keystone,dims/keystone,ilay09/keystone,mahak/keystone,ilay09/keystone,rushiagr/keystone,promptworks/keystone,MaheshIBM/keystone,dsiddharth/access-keys