Fix event pipe ZMQ context

Author: davidbrochart

ipykernel/iostream.py

@@ -143,7 +143,7 @@ def _event_pipe(self):
             event_pipe = self._local.event_pipe
         except AttributeError:
             # new thread, new event pipe
-            ctx = self.socket.context
+            ctx = zmq.Context(self.socket.context)
             event_pipe = ctx.socket(zmq.PUSH)
             event_pipe.linger = 0
             event_pipe.connect(self._event_interface)