overcloud status: return a message if no deployment is found

If "openstack overcloud status" has no deployment, returns a proper
message instead of just None.

Change-Id: Ia884a052223be31e8df9de8ae39dacd1fc3159cd
(cherry picked from commit 71135833d9)

tripleoclient/v1/overcloud_deploy.py

@@ -1044,6 +1044,7 @@ class GetDeploymentStatus(command.Command):
         )
 
         if not status:
+            print('No deployment was found for %s' % plan)
             return
 
         payload = status['workflow_status']['payload']