Putting connection file cleanup back in __del__.

IPython/zmq/kernelmanager.py

@@ -706,6 +706,9 b' class KernelManager(Configurable):'
     _stdin_channel = Any
     _hb_channel = Any
     _connection_file_written=Bool(False)
+ 	
+    def __del__(self):	  	
+        self.cleanup_connection_file()
 
     #--------------------------------------------------------------------------
     # Channel management methods: