Author: Petr Skoda
MDL-23984 removing unused error string
http://git.moodle.org/gw?p=moodle.git;a=commit;h=77f6cb83c02e7363cce460d1fe9a6ae63fd9775a
http://github.com/moodle/moodle/commit/77f6cb83c02e7363cce460d1fe9a6ae63fd9775a
- 2.0 en [nopermissiontomkdir,core_error]