cleanup socket cleanup

- set linger on sockets (avoid hang on exit)
- actually close sockets, not just zmq streams (blame pyzmq, aka me)

seems to be necessary for js/notebook/shutdown test to avoid hanging on Python 3.4.

IPython/html/services/kernels/handlers.py

@@ -127,7 +127,10 b' class ZMQChannelHandler(AuthenticatedZMQStreamHandler):'
         # closed before the ZMQ streams are setup, they could be None.
         if self.zmq_stream is not None and not self.zmq_stream.closed():
             self.zmq_stream.on_recv(None)
+            # close the socket directly, don't wait for the stream
+            socket = self.zmq_stream.socket
             self.zmq_stream.close()
+            socket.close()
 
 
 class IOPubHandler(ZMQChannelHandler):

IPython/kernel/connect.py

@@ -524,6 +524,8 b' class ConnectionFileMixin(Configurable):'
         socket_type = channel_socket_types[channel]
         self.log.debug("Connecting to: %s" % url)
         sock = self.context.socket(socket_type)
+        # set linger to 1s to prevent hangs at exit
+        sock.linger = 1000
         if identity:
             sock.identity = identity
         sock.connect(url)