ZEROMQ fails to close ports when scripts ended

[lottiegreenwood]

Even after killing all python processes, when rerunning scripts, errors show about ports being still in use

2016-05-09 14:00:30.667 - INFO - backend_event_listener - Starting EventListener...
2016-05-09 14:00:30.667 - INFO - backend_event_listener - Connected to event streamer at tcp://localhost:10001
Exception in thread Thread-2:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "backend/zmq_queue.py", line 26, in run
    self._connect(self._host, self._port)
  File "backend/zmq_queue.py", line 43, in _connect
    self._socket.bind(uri)
  File "socket.pyx", line 434, in zmq.backend.cython.socket.Socket.bind (zmq/backend/cython/socket.c:3928)
  File "checkrc.pxd", line 21, in zmq.backend.cython.checkrc._check_rc (zmq/backend/cython/socket.c:6058)
ZMQError: Address already in use