Make ControlThread daemonic

Author: SylvainCorlay

ipykernel/control.py

@@ -10,9 +10,8 @@
 
 class ControlThread(Thread):
 
-    def __init__(self, context):
-        Thread.__init__(self)
-        self.context = context
+    def __init__(self, **kwargs):
+        Thread.__init__(self, **kwargs)
         self.io_loop = IOLoop(make_current=False)
 
     def run(self): 

ipykernel/kernelapp.py

@@ -300,7 +300,7 @@ def init_control(self, context):
             # see ipython/ipykernel#270 and zeromq/libzmq#2892
             self.control_socket.router_handover = 1
 
-        self.control_thread = ControlThread(self.control_socket)
+        self.control_thread = ControlThread(daemon=True)
         self.control_thread.start()
 
     def init_iopub(self, context):