change cinder SC to use $(project_id)
change cinder SC to use $(project_id)

This removes another place where we reference tenant_id

Change-Id: I88fa1c5475105c301b27672b028bddb289f9c108

group-policy/devstack,bswartz/devstack,bigswitch/devstack,noironetworks/devstack,bigswitch/devstack,openstack-dev/devstack,noironetworks/devstack,nawawi/openstack,dtroyer/devstack,nawawi/openstack,group-policy/devstack,openstack-dev/devstack,bswartz/devstack,Mahito/devstack,dtroyer/devstack,richliu/devstack,Mahito/devstack,richliu/devstack