Author: sam marshall
MDL-60943 core_search: Improve exception for preg_replace errors
http://git.moodle.org/gw?p=moodle.git;a=commit;h=0ce4a248881a7c3ece6e3dc5ae7140c9dae5daad
http://github.com/moodle/moodle/commit/0ce4a248881a7c3ece6e3dc5ae7140c9dae5daad
+ 3.4 en [error_indexing,core_search]