Git commits in Moodle 3.5.8 by Ilya Tregubov

commit 9f51263a377bf9f4ad7fa6bd78e865dcc02dbe84
Author: Ilya Tregubov <ilyatregubov@catalyst-au.net>
Date:   Mon, 17 Jun 2019 13:37:32 +0800
Tag:    v3.5.8

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