Git commits in Moodle 3.3.x by Marcus Boon

commit 98bd6c527346ce5983bf234fae316f87f824e552
Author: Marcus Boon <marcus@catalyst-au.net>
Date:   Thu, 13 Jul 2017 12:44:29 +0800
Tag:    v3.3.4

MDL-59866 session: Add retry for redis sessions