mod_voipms: Fix bug from not returning in message/bare hook Since SMS/MMS are sent/received on JIDs that are not real accounts, we need to `return true` from the 'message/bare' hook, otherwise routing will occur and result in failed account lookups.

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.