Git commits in Moodle 3.2.x by Andres Melo

commit a4ad655bf1f9b4da35d52d250db7b3bf7c93c0d7
Author: Andres Melo <andresmelo@iMac-de-JuanPaez.local>
Date:   Thu, 18 May 2017 04:54:40 +0800
Tag:    v3.2.4

MDL-46322 mod_assign: Only list enrolled graders as potential markers