Git commits in Moodle 3.8.0 by Dan Marsden

commit 22dfa6d31dcb2f5fb6f47b819fa83d739c4547ac
Author: Dan Marsden <dan@danmarsden.com>
Date:   Tue, 14 May 2019 17:55:34 +0800
Tag:    v3.8.0-beta

MDL-60347 core: debugsmtp should be a developer only setting.