Author: Botond Hegedus
MDL-49198 core_webservice: Fix error when using existing service name
http://git.moodle.org/gw?p=moodle.git;a=commit;h=bd3332ff6eb1b8d0edde6fc7258f02321bfc56a2
http://github.com/moodle/moodle/commit/bd3332ff6eb1b8d0edde6fc7258f02321bfc56a2
+ 2.7 en [nameexists,core_webservice]