Author: Tim Hunt
MDL-48008 gradeimport_xml: report errors usefully
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b4a40e451da3651ec1823507c9fb3b6f4be2c7b8
http://github.com/moodle/moodle/commit/b4a40e451da3651ec1823507c9fb3b6f4be2c7b8
+ 2.8 en [errorduringimport,gradeimport_xml]