Git commits in Moodle 3.5.3 by Dan Marsden

commit 4aa5cee144ceaebd0f7e024cddb7e85adfbc91a7
Author: Dan Marsden <dan@danmarsden.com>
Date:   Tue, 06 Nov 2018 04:57:36 +0800
Tag:    v3.5.3

MDL-63800 mod_assign: don't show grade if not set.