Author: Zig Tan
MDL-61881 report_usersessions: Implement null privacy provider
http://git.moodle.org/gw?p=moodle.git;a=commit;h=184f7d3a85de095cf58eff280a5d864275dc198d
http://github.com/moodle/moodle/commit/184f7d3a85de095cf58eff280a5d864275dc198d
+ 3.4 en [privacy:metadata,report_usersessions]