Author: Aaron Barnes
MDL-37473 completion: Add missing cap checks to tracked users functions
Namely get_num_tracked_users and is_tracked_user()
http://git.moodle.org/gw?p=moodle.git;a=commit;h=10a8581f2bcdf4edf6f73ad23ce9ef5ce2033dd9
http://github.com/moodle/moodle/commit/10a8581f2bcdf4edf6f73ad23ce9ef5ce2033dd9
+ 2.5 en [nottracked,core_completion]