Misc: Fix log message on invalid commands in private

It showed 'Not replying to <command> in None,', since channel is None in
private (unlike the former msg.args[0], which was the bot's nick).

I wasn't careful enough when I replaced msg.args[0] with msg.channel
across the codebase.

plugins/Misc/plugin.py

@@ -168,8 +168,7 @@ class Misc(callbacks.Plugin):
                 # echo [] will get us an empty token set, but there's no need
                 # to log this in that case anyway, it being a nested command.
                 self.log.info('Not replying to %s in %s, not a command.',
-                    tokens[0], channel
-                    if channel != irc.nick else _('private'))
+                    tokens[0], channel or _('private'))
             if irc.nested:
                 bracketConfig = conf.supybot.commands.nested.brackets
                 brackets = bracketConfig.getSpecific(irc.network, channel)()