mod_adhoc_oauth2_client: Fix including final client_id in result form The client_id is composed of the details needed for retrieving the data, making it redundant to include in the data, albeit somewhat convenient sometimes. Decided to remove it anyways, but forgot to change the result.

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.