Fix #36

Don't start listener if it doesn't contain a 'bind' parameter

hbmqtt/broker.py

@@ -225,6 +225,9 @@ class Broker:
             for listener_name in self.listeners_config:
                 listener = self.listeners_config[listener_name]
 
+                if 'bind' not in listener:
+                    self.logger.debug("Listener configuration '%s' is not bound" % listener_name)
+                else:
                     # Max connections
                     try:
                         max_connections = listener['max_connections']