Author: David Mudrák
MDL-48165 workshop: Validate the rubric editing form
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a0c74d2ad9eac29c98ae1cb62858ca20d833874e
http://github.com/moodle/moodle/commit/a0c74d2ad9eac29c98ae1cb62858ca20d833874e
+ 2.9 en [mustbeunique,workshopform_rubric]