Don't fake a close code in close response

If the peer doesn't send us a close code, then don't send any code back
in the response. Sending 1005 is explicitly wrong as the specification
states that code should only be used locally and never be sent over the
network.

websockify/websocket.py

@@ -666,7 +666,7 @@ def _recvmsg(self):
                             continue
 
                 if code is None:
-                    self.close_code = code = 1005
+                    self.close_code = 1005
                     self.close_reason = "No close status code specified by peer"
                 else:
                     self.close_code = code