Author: Shamim Rezaie
MDL-62059 mod_book: Implement null provider for mod_book
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c287f0fdd9227dfdc94d011126d3f7c913cad039
http://github.com/moodle/moodle/commit/c287f0fdd9227dfdc94d011126d3f7c913cad039
+ 3.5 en [privacy:metadata,mod_book]