Git merges in Moodle 2.7.18 by Eloy Lafuente (stronk7)

commit 6ee651714249589216687de7c442d98ac2ecf384
Author: Eloy Lafuente (stronk7) <stronk7@moodle.org>
Date:   Sun, 08 Jan 2017 18:04:10 +0800
Tag:    v2.7.18

Merge branch 'install_27_STABLE' of https://git.in.moodle.com/amosbot/moodle-install into MOODLE_27_STABLE