Git commits in Moodle 3.1.17 by Damyon Wiese

commit 772c908d40a944efd91d897d524b255626d330d4
Author: Damyon Wiese <damyon@moodle.com>
Date:   Tue, 29 Jan 2019 09:23:36 +0800
Tag:    v3.1.17

MDL-64651 comments: Do not send referrer