Git commits in Moodle 2.6.3 by Jonathan Champ

commit 338fd396b7f1c2b925e6219ba790c76ff025b490
Author: Jonathan Champ <jonathan_champ@ncsu.edu>
Date:   Thu, 20 Mar 2014 23:04:41 +0800
Tag:    v2.6.3

MDL-29572 Grade Import: Avoid creating invalid temporary rows; Provide feedback on error