Author: Ankit Kumar Agarwal
MDL-30398 Validations added for password field
http://git.moodle.org/gw?p=moodle.git;a=commit;h=0c6182c125d8db51df6c3d089ba5c4eaea2decf8
http://github.com/moodle/moodle/commit/0c6182c125d8db51df6c3d089ba5c4eaea2decf8
+ 2.0 en [emptypassword,mod_lesson]