Fixes instance action exception in "evacuate" API.

'Evacuate' instance action was not created (incl. in the DB) which
caused exception to be raised during action_event_start.

Change-Id: Iec5f0a91f9b08fbdcf3ace1eaa0efbc4d9d8fc04
Fixes: bug 1152512

nova/compute/api.py

@@ -2470,6 +2470,9 @@ class API(base.Base):
 
         instance = self.update(context, instance, expected_task_state=None,
                                task_state=task_states.REBUILDING)
+
+        self._record_action_start(context, instance, instance_actions.EVACUATE)
+
         return self.compute_rpcapi.rebuild_instance(context,
                                         instance=instance,
                                         new_pass=admin_password,

nova/compute/instance_actions.py

@@ -27,6 +27,7 @@ they are used.
 
 CREATE = 'create'
 DELETE = 'delete'
+EVACUATE = 'evacuate'
 RESTORE = 'restore'
 STOP = 'stop'
 START = 'start'