Author: jerome mouneyrac
webservice MDL-23440 more explicit error message when validation context fail in some external functions (missing lang file modification).
http://git.moodle.org/gw?p=moodle.git;a=commit;h=e21c56bdb05fe9c422f59d845adf8ee32c5fab05
http://github.com/moodle/moodle/commit/e21c56bdb05fe9c422f59d845adf8ee32c5fab05
+ 2.0 en [errorcoursecontextnotvalid,core_webservice]