Git commits in Moodle 3.3.3 by Davo Smith

commit cdd6d0d240ef12387c878b4273f5b7d3fdc76740
Author: Davo Smith <davo.smith@synergy-learning.com>
Date:   Fri, 06 Oct 2017 19:46:05 +0800
Tag:    v3.3.3

MDL-60366 mod_feedback: fix deletion of valid anonymous duplicates