Author: Zig Tan
MDL-61881 report_questioninstances: Implement null privacy provider
http://git.moodle.org/gw?p=moodle.git;a=commit;h=2b0b91d7ee6169d185bc86031875955c2bc6a95c
http://github.com/moodle/moodle/commit/2b0b91d7ee6169d185bc86031875955c2bc6a95c
+ 3.5 en [privacy:metadata,report_questioninstances]