Git commits in Moodle 2.8.9 by Jakob

commit 57d281f55437918d2d1b9226f3826446bb014682
Author: Jakob <jackermann@onlineschool.ca>
Date:   Wed, 04 Nov 2015 02:41:03 +0800
Tag:    v2.8.9

MDL-51899 mod/assign: Allow 0.00 grades while editing a grade.