Assign further_work either way.

module_build_service/scheduler/consumer.py

@@ -197,6 +197,7 @@ class MBSConsumer(fedmsg.consumers.FedmsgConsumer):
                 if build:
                     further_work = handler(conf, session, msg) or []
                 else:
+                    further_work = []
                     log.warn("There's no module associated with message ID {}"
                              .format(msg.msg_id))
             except ValidationError as e: