Git commits in Moodle 3.8.x by Anthony Forth

commit c47d17b93bb944d98b236a3e3ecd63c5ec6283b2
Author: Anthony Forth <a.j.forth@open.ac.uk>
Date:   Wed, 12 Feb 2020 20:26:16 +0800
Tag:    v3.8.2

MDL-67945 enrol: missing $DB in edit_instance_form