Add db_version command to keystone-manage
Add db_version command to keystone-manage

The db_version command simply looks at the database and prints the
version to which the database has been migrated.

Change-Id: I50098bf1aa6d57883cc9acc0c4d09d9c8448db7f

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