never use Queue.get(timeout=None)

Queue.get(timeout=None) has stupid uninterruptible behavior,
so wait for a week instead.

IPython/zmq/blockingkernelmanager.py

@@ -35,6 +35,10 b' class BlockingChannelMixin(object):'
         
     def get_msg(self, block=True, timeout=None):
         """ Gets a message if there is one that is ready. """
+        if timeout is None:
+            # Queue.get(timeout=None) has stupid uninteruptible
+            # behavior, so wait for a week instead
+            timeout = 604800
         return self._in_queue.get(block, timeout)
         
     def get_msgs(self):