Enable notifications about vm state on controller

In order to ceilometer can properly generate samples about vm state
change, we need to enable vm state change notifications on nova
controller.

Change-Id: Icdad48df6800c2db8efe5bf9207309690d12191c
Related-Prod: https://mirantis.jira.com/browse/PROD-17879
diff --git a/ceilometer/client/nova_control.yml b/ceilometer/client/nova_control.yml
index 252c67e..7ac8f89 100644
--- a/ceilometer/client/nova_control.yml
+++ b/ceilometer/client/nova_control.yml
@@ -3,3 +3,5 @@
     controller:
       notification:
         driver: messagingv2
+        notify_on:
+          state_change: vm_and_task_state