Author: David Monllao
MDL-55287 search: Check that an engine has been selected
http://git.moodle.org/gw?p=moodle.git;a=commit;h=379ca986421e7e1e3d639591c061214d96beef06
http://github.com/moodle/moodle/commit/379ca986421e7e1e3d639591c061214d96beef06
+ 3.2 en [enginenotinstalled,core_search]
+ 3.2 en [enginenotselected,core_search]