mod_http_oauth2: Fix inclusion of role in refreshed access tokens `refresh_token_info` does not carry the role, and due to behavior prior to prosody trunk rev a1ba503610ed it would have reverted to the users' default role. After that it instead issues a token without role which is thus not usable with e.g. mod_rest

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.