remove uneeded code

Author: echarles

ipykernel/kernelbase.py

@@ -857,7 +857,6 @@ async def debug_request(self, stream, ident, parent):
         if inspect.isawaitable(reply_content):
             reply_content = await reply_content
         reply_content = json_clean(reply_content)
-        reply_content['hello'] = 'hello'
         reply_msg = self.session.send(stream, 'debug_reply', reply_content,
                                       parent, ident)
         self.log.debug("%s", reply_msg)