deleting a comm now unregisters the comm. unrehistering the comm does not close it anymore

IPython/kernel/comm/comm.py

@@ -70,6 +70,7 b' class Comm(LoggingConfigurable):'
     def __del__(self):
         """trigger close on gc"""
         self.close()
+        get_ipython().comm_manager.unregister_comm(self)
     
     # publishing messages
     

IPython/kernel/comm/manager.py

@@ -76,7 +76,6 b' class CommManager(LoggingConfigurable):'
         """Unregister a comm, and close its counterpart"""
         # unlike get_comm, this should raise a KeyError
         comm = self.comms.pop(comm_id)
-        comm.close()
     
     def get_comm(self, comm_id):
         """Get a comm with a particular id