Add expected exception to aggregate_metadata_delete()

This adds a missing client_exceptions() decorator to the conductor's
aggregate_metadata_delete() method, which was missed due to the
timing of when the patches landed. With this, all expected exceptions
in conductor's current set of operations should be properly marked.

Related to bp/no-db-compute-manager

Change-Id: Ifa8cdcb1c7e93aeb95f5dc4fe2e294fe0165cdc5

nova/conductor/manager.py

@@ -118,6 +118,7 @@ class ConductorManager(manager.SchedulerDependentManager):
                                                       metadata, set_delete)
         return jsonutils.to_primitive(new_metadata)
 
+    @rpc_common.client_exceptions(exception.AggregateMetadataNotFound)
     def aggregate_metadata_delete(self, context, aggregate, key):
         self.db.aggregate_metadata_delete(context.elevated(),
                                           aggregate['id'], key)