Author: Cameron Ball
MDL-21912 restore: Add admin setting to restore conflicting admin user
http://git.moodle.org/gw?p=moodle.git;a=commit;h=088d6086d876365541d0402ee04db2d8ac49e4c0
http://github.com/moodle/moodle/commit/088d6086d876365541d0402ee04db2d8ac49e4c0
+ 3.1 en [importgeneralduplicateadminallowed,core_backup]
+ 3.1 en [importgeneralduplicateadminallowed_desc,core_backup]
+ 3.1 en [restoremnethostidmismatch,core]