Author: David Mudrák
MDL-35238 Warn the admin if they are about to overwrite a SCM checkout
http://git.moodle.org/gw?p=moodle.git;a=commit;h=08c3bc006d6e9486547e96ad194bb6ad6ffad885
http://github.com/moodle/moodle/commit/08c3bc006d6e9486547e96ad194bb6ad6ffad885
+ 2.4 en [updatepluginconfirmexternal,core_plugin]