Author: Jean-Michel Vedrine
MDL-63905 qtype_multianswer: validate imported questions
http://git.moodle.org/gw?p=moodle.git;a=commit;h=48aad79a6344457dcec67988e86c1d17dc4a669e
http://github.com/moodle/moodle/commit/48aad79a6344457dcec67988e86c1d17dc4a669e
+ 3.7 en [invalidmultianswerquestion,qtype_multianswer]