[agent] Convert all unicode input to str before zmq sending

beat/core/agent.py

@@ -191,7 +191,7 @@ class Server(gevent.Greenlet):
       self.socket.send(str(inputs_to_go), zmq.SNDMORE)
       for inp in channel_group:
         logger.debug('send: %s', inp.name)
-        self.socket.send(inp.name, zmq.SNDMORE)
+        self.socket.send(str(inp.name), zmq.SNDMORE)
         if inp.data is None:
           message = "User algorithm process asked for more data on channel " \
                   "`%s' (all inputs), but input `%s' has nothing. This " \