mod_blocklist: Fix fix signal for letting stanzas pass
Returning nothing/nil lets stanzas pass, returning anything else blocks
-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
module:set_global(); -- we're a global module
-- TODO delete this whole concept