Pass the query object to _close_comments_for_old_posts() so that is_singular...

Pass the query object to _close_comments_for_old_posts() so that is_singular is checked for the proper query.  Props kawauso. fixes #18109

git-svn-id: https://core.svn.wordpress.org/trunk@18836 1a063a9b-81f0-0310-95a4-ce76da25c4cd