[Mimedefang] uol.com.br rule

[Kenneth Porter]

There's some brain-dead challenge response causing grief on the 
fedora-users and spamassassin lists. Here's my rule for rejecting them. I 
have it before the message_rejected() check in filter_end().

    if ($Sender =~ /sspam\@uol\.com\.br/i)
    {
        action_discard_bounce("We don't do Challenge-Response");
    }