Git commits in Moodle 3.5.1 by Tobias Reischmann

commit c8511e28088edb12c6434540c5243fd44243a69e
Author: Tobias Reischmann <tobias.reischmann@wi.uni-muenster.de>
Date:   Wed, 23 May 2018 20:05:28 +0800
Tag:    v3.5.1

MDL-62543 forum: Switched the usage of the deleted flag for rss