There is no need to set VM status to ERROR on a failed migration

VM state should not be set to ERROR, when the
migration failed beauce libvirt is unavailble on the destination.

Fixes bug #1233184
Change-Id: I36e4ed3842d7e33c1082ec95f860629eee23224e

nova/conductor/manager.py

@@ -712,8 +712,8 @@ class ComputeTaskManager(base.Base):
                 filter_properties=filter_properties, node=node)
         except Exception as ex:
             with excutils.save_and_reraise_exception():
-                updates = {'vm_state': vm_states.ERROR,
-                            'task_state': None}
+                updates = {'vm_state': instance['vm_state'],
+                           'task_state': None}
                 self._set_vm_state_and_notify(context, 'migrate_server',
                                               updates, ex, request_spec)
                 if reservations:
@@ -738,6 +738,7 @@ class ComputeTaskManager(base.Base):
                 exception.DestinationHypervisorTooOld,
                 exception.InvalidLocalStorage,
                 exception.InvalidSharedStorage,
+                exception.HypervisorUnavailable,
                 exception.MigrationPreCheckError) as ex:
             with excutils.save_and_reraise_exception():
                 #TODO(johngarbutt) - eventually need instance actions here
@@ -751,14 +752,11 @@ class ComputeTaskManager(base.Base):
                              expected_task_state=task_states.MIGRATING,),
                         ex, request_spec, self.db)
         except Exception as ex:
-            with excutils.save_and_reraise_exception():
-                request_spec = {'instance_properties': {
-                    'uuid': instance['uuid'], },
-                }
-                scheduler_utils.set_vm_state_and_notify(context,
-                        'compute_task', 'migrate_server',
-                        {'vm_state': vm_states.ERROR},
-                        ex, request_spec, self.db)
+            LOG.error(_('Migration of instance %(instance_id)s to host'
+                       ' %(dest)s unexpectedly failed.'),
+                       {'instance_id': instance['uuid'], 'dest': destination},
+                       exc_info=True)
+            raise exception.MigrationError(reason=ex)
 
     def build_instances(self, context, instances, image, filter_properties,
             admin_password, injected_files, requested_networks,