Fix devstack plugin setup
Fix devstack plugin setup

We were checking if KEYSTONE_CATALOG_BACKEND when setting up senlin
service. This seems pointless and it is now rendering the gate jobs
failing.

Change-Id: I9edd08a0fa05994856a394d34ef43402acf3ced8

stackforge/senlin,openstack/senlin,stackforge/senlin,openstack/senlin,openstack/senlin