Don't notify friendfeed for unchecked content types

I noticed the module was posting to friendfeed even for content types I had unchecked. I was able to fix it by changing this (in the friendfeed_nodeapi method):

      $types = isset($user->friendfeed_contenttypes) ?  $user->friendfeed_contenttypes : array();

to this: (from p.262 of pro drupal development, 2nd ed)

        $types = array_filter($user->friendfeed_contenttypes);