Git commits in Moodle 2.7.4 by Huy Hoang

commit 5b29dbc7812aa5238e0daf9f41efa7a962539d86
Author: Huy Hoang <hoang027@umn.edu>
Date:   Mon, 10 Nov 2014 12:14:31 +0800
Tag:    v2.7.4

MDL-39692 grade: Ability to delete letter boundary