Author: Jetha Chan
MDL-36009 grader_gradereport: filler and extra user cells should not be headers
http://git.moodle.org/gw?p=moodle.git;a=commit;h=6929b68bd01dd4c269715ab0e375076086fe5c82
http://github.com/moodle/moodle/commit/6929b68bd01dd4c269715ab0e375076086fe5c82
+ 2.9 en [summarygrader,gradereport_grader]