Author: Jean-Michel Vedrine
MDL-26689 mod_lesson: deprecate lesson dependency
http://git.moodle.org/gw?p=moodle.git;a=commit;h=e8a434b3738b1b67582eb194927c4f879890a5ca
http://github.com/moodle/moodle/commit/e8a434b3738b1b67582eb194927c4f879890a5ca
+ 2.9 en [prerequisiteisobsolete,mod_lesson]
+ 2.9 en [warning,mod_lesson]