From: Eduardo Felipe <eduardofelipe87@gmail.com>

From: Eduardo Felipe <eduardofelipe87@gmail.com>
Upon creating a timer, it's callback must return an int, otherwise it
would panic. The python bindings do the nicety of, if the callback
function returns nothing, automatically canceling the reschedule of
the timer.

This patch does the same for lua. It's a oneliner.

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/edje@49051 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33