api-paste.ini: use new keystone library
api-paste.ini: use new keystone library

Change-Id: I3140cdfd6c1d033f5ad6691298ac66e7ce37a0d4

priya-pp/Tacker,stackforge/tacker,openstack/tacker,trozet/tacker,openstack/tacker,SripriyaSeetharam/tacker,openstack/tacker,SripriyaSeetharam/tacker,zeinsteinz/tacker,trozet/tacker,priya-pp/Tacker,zeinsteinz/tacker,stackforge/tacker