Author: Mark Nelson
MDL-30377 forum: do not allow users to view not yet started or expired discussions
http://git.moodle.org/gw?p=moodle.git;a=commit;h=73d13b1e4320082fe6cf6ccb2ccca3d9faba5dcb
http://github.com/moodle/moodle/commit/73d13b1e4320082fe6cf6ccb2ccca3d9faba5dcb
+ 2.3 en [forumbodyhidden,mod_forum]