Don't try to add new users if we're changing usermodes on ourselves.

The actor in this case will either be ourself (in which case users.Bot
already exists), or a services nick (which may not have a full hostmask,
and therefore cause hashing errors). Only try to add a user if we're
changing a channel mode. This may still break on chanmodes, needs more
testing in that regard.

src/hooks.py

@@ -316,11 +316,11 @@ def mode_change(cli, rawnick, chan, mode, *targets):
 
     """
 
-    actor = users._add(cli, nick=rawnick) # FIXME
     if chan == users.Bot.nick: # we only see user modes set to ourselves
         users.Bot.modes.update(mode)
         return
 
+    actor = users._add(cli, nick=rawnick) # FIXME
     target = channels.add(chan, cli)
     target.queue("mode_change", {"mode": mode, "targets": targets}, (var, actor, target))