Author: Andrew Nicols
MDL-62326 core_antivirus: Implement null provider
http://git.moodle.org/gw?p=moodle.git;a=commit;h=e00c025ed6be8ecdddc8fd6ebc7ba88ff7d029c2
http://github.com/moodle/moodle/commit/e00c025ed6be8ecdddc8fd6ebc7ba88ff7d029c2
+ 3.4 en [privacy:metadata,core_antivirus]