mod_firewall: Fix 'is_admin' internal dependency rule #1797 (thanks diane) Looks like the boolean logic was inverted here. Instead, for now, simply check if is_admin is there. It is deprecated in trunk and was briefly removed before being brought back with a 'deprecated' warning as part of the new roles and permissions work. Making this dependency conditioned on the existence of the underlying function should make it work until it actually goes away for real.

This module adds a command to `prosodyctl` for listing users.

``` sh
prosodyctl mod_listusers
```