Added check_password to abstract backend user API
Added check_password to abstract backend user API

Change-Id: Ibb05f7842ae6e2b1f42c9956aee20a72472c3cef

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