Git commits in Moodle 3.8.0 by Leon Stringer

commit 50960244d8eccde9cbefdba86976839a75bf86dd
Author: Leon Stringer <leon@priorsvle.com>
Date:   Thu, 11 Apr 2019 19:24:12 +0800
Tag:    v3.8.0-beta

MDL-59911 fileconverter_unoconv: Fix: test PDF fails after upgrade