Git merges in Moodle 3.4.0 by AMOS bot

commit b87f163a1b63690bddaedde80d18f83778a5420a
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 24 Jun 2017 00:08:36 +0800
Tag:    v3.4.0-beta

Merge branch 'master' into install_master