Author: Zig Tan
MDL-61881 report_questioninstances: Implement null privacy provider
http://git.moodle.org/gw?p=moodle.git;a=commit;h=850bbe3b9782162a67800fe501c4a0a5837015d6
http://github.com/moodle/moodle/commit/850bbe3b9782162a67800fe501c4a0a5837015d6
+ 3.4 en [privacy:metadata,report_questioninstances]