Git commits in Moodle 3.6.3 by Eric Merrill

commit b2ac807c9fc1af8db37310bcc8029771f089bd7c
Author: Eric Merrill <merrill@oakland.edu>
Date:   Wed, 23 Jan 2019 10:40:12 +0800
Tag:    v3.6.3

MDL-64609 gradebook: Prevent infinite loop in regrading