Git commits in Moodle 3.6.6 by Ilya Tregubov

commit 40b81687d6570ab26d4a1ec827e323bfc98e3a00
Author: Ilya Tregubov <ilyatregubov@catalyst-au.net>
Date:   Mon, 17 Jun 2019 13:37:32 +0800
Tag:    v3.6.6

MDL-65925 assign: Grade page broken if submission was deleted.