Author: Jean-Philippe Gaudreau
MDL-34819: CAS authentication : Alternative logout return URL
http://git.moodle.org/gw?p=moodle.git;a=commit;h=7d6974312f17b627f6db871a9414c3d28a5bc448
http://github.com/moodle/moodle/commit/7d6974312f17b627f6db871a9414c3d28a5bc448
+ 2.4 en [auth_cas_logout_return_url_key,auth_cas]
+ 2.4 en [auth_cas_logout_return_url,auth_cas]