Git commits in Moodle 3.6.x by Frédéric Massart

commit dd815d254f3a5ceb06b5e9b43dc28174c95a9118
Author: Frédéric Massart <fred@branchup.tech>
Date:   Fri, 20 Oct 2017 17:24:08 +0800
Tag:    v3.6.2

MDL-60518 core_user: A user with ID 0 is never a real user