Replace fixtures with mock in test_keystone.py
Replace fixtures with mock in test_keystone.py

Change-Id: I83b5035c6919ced43cb4b39ae233976a3a06fa76

debayanray/ironic_backup,NaohiroTamura/ironic,pshchelo/ironic,naototty/vagrant-lxc-ironic,Tan0/ironic,ramineni/myironic,JioCloud/ironic,naototty/vagrant-lxc-ironic,faizan-barmawer/openstack_ironic,rackerlabs/ironic,dims/ironic,hpproliant/ironic,dims/ironic,redhat-openstack/ironic,bacaldwell/ironic,devananda/ironic,froyobin/ironic,bacaldwell/ironic,NaohiroTamura/ironic,supermari0/ironic,rdo-management/ironic,varunarya10/ironic,openstack/ironic,pshchelo/ironic,naterh/ironic,ionutbalutoiu/ironic,SauloAislan/ironic,ionutbalutoiu/ironic,openstack/ironic,Tehsmash/ironic,SauloAislan/ironic