squash: Simplify rules.

An error for indexing nil we observe.

resources/prosody-plugins/mod_muc_allowners.lua

@@ -133,6 +133,12 @@ function filter_admin_set_query(event)
     local room = get_room_from_jid(room_jid);
 
     local item = stanza.tags[1].tags[1];
+
+    if not item then
+        module:log('error', 'Error unexpected stanza: %s', stanza);
+        return true;
+    end
+
     local _aff = item.attr.affiliation;
 
     -- if it is a moderated room we skip it
@@ -141,7 +147,7 @@ function filter_admin_set_query(event)
     end
 
     -- any revoking is disabled, everyone should be owners
-    if _aff == 'none' or _aff == 'outcast' or _aff == 'member' then
+    if _aff and _aff ~= 'owner' then
         origin.send(st.error_reply(stanza, "auth", "forbidden"));
         return true;
     end