Author: Zig Tan
MDL-61881 report_questioninstances: Implement null privacy provider
http://git.moodle.org/gw?p=moodle.git;a=commit;h=63de5af9688a72ecf3453940d878e337062e7625
http://github.com/moodle/moodle/commit/63de5af9688a72ecf3453940d878e337062e7625
+ 3.3 en [privacy:metadata,report_questioninstances]