Author: sam marshall
MDL-60943 core_search: Improve exception for preg_replace errors
http://git.moodle.org/gw?p=moodle.git;a=commit;h=d51a8d2e4039a7380d2c6e47f450d1d15323ae89
http://github.com/moodle/moodle/commit/d51a8d2e4039a7380d2c6e47f450d1d15323ae89
+ 3.3 en [error_indexing,core_search]