don't create a new, copied list in get_project_users
don't create a new, copied list in get_project_users

also replace other for loops with list iterations

Change-Id: I3d6dc40f108b6f235a6c6d43a867c91845f442cd

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