Git commits in Moodle 3.7.x by Anthony Forth

commit cb2a49009ccc8c1f7e7b2fd96197ede7e76cdc1f
Author: Anthony Forth <a.j.forth@open.ac.uk>
Date:   Wed, 12 Feb 2020 20:26:16 +0800
Tag:    v3.7.5

MDL-67945 enrol: missing $DB in edit_instance_form