mod_muc_rtbl: move use of "private" attributes to single function This way, we reduce the scope where you can have a typo in the attribute name to that function and we encourage users to actually always call update_hashes.

---
summary: Store authentication events in the audit log
rockspec:
  dependencies:
  - mod_audit
...

This module stores authentication failures and authentication successes in the
audit log provided by `mod_audit`.