Git commits in Moodle 3.9.0 by hanna

commit 078705538cfd17e3fbe7ee4feb76c9bf606f53fd
Author: hanna <hanna.edelman@weizmann.ac.il>
Date:   Thu, 05 Dec 2019 00:51:09 +0800
Tag:    v3.9.0-beta

MDL-67456 admin: Update Maximum number of backups kept