mod_http_oauth2: Correct field name for HTTP response status code 'code' is used in the incoming side of the Prosody HTTP stack while 'status_code' is used on the response side. Not confusing at all. The default is 200 so this mistake had no real effect.

This module writes out a traceback to `traceback.txt` in Prosodys data
directory (see `prosodyctl about`) when the signal `SIGUSR1` is
received. This is useful when debugging seemingly frozen instances in
case it is stuck in Lua code.