Revert "websockets: continue listening for messages after parsing com…

…pletion"

This reverts commit 9ea5f8a.

The one-shot behavior of receive_message was intentional, and simply
requeuing the old callback every time will eventually overflow the
stack due to repeated async_callback wrappers.  An alternate interface
that doesn't require receive_message to be called for every message
may be added in a future change.

See discussion at
http://github.com/facebook/tornado/commit/9ea5f8a277db96557ae7867375c7db4d8c5f633a

tornado/websocket.py

@@ -127,7 +127,6 @@ def _on_frame_type(self, callback, byte):
 
     def _on_end_delimiter(self, callback, frame):
         callback(frame[:-1].decode("utf-8", "replace"))
-        self.receive_message(callback)
 
     def _not_supported(self, *args, **kwargs):
         raise Exception("Method not supported for Web Sockets")