Git merges in Moodle 3.5.2 by Alberto Lara Hernández

commit 4c51211800729db9a07c66715fb7d3266e3157b0
Author: Alberto Lara Hernández <alberto.lara@moodle.com>
Date:   Mon, 03 Sep 2018 18:34:14 +0800
Tag:    v3.5.2

Merge branch 'MDL-55993-35' of https://github.com/albertolarah/moodle into MDL-55993-35