Author: Tim Hunt
MDL-32404 question export: missing error message when exporting an empty category.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=e0538fa8451652fb5d3367175c48a07893242e7d
http://github.com/moodle/moodle/commit/e0538fa8451652fb5d3367175c48a07893242e7d
+ 2.2 en [noquestions,core_question]