Git commits in Moodle 3.1.5 by Adam Olley

commit c36e94ad983fe7ab38820a59e6777c9f41b99d6b
Author: Adam Olley <adam.olley@blackboard.com>
Date:   Tue, 21 Feb 2017 12:01:19 +0800
Tag:    v3.1.5

MDL-58030 gradingform_guide: Init $commentchooser before use