force CENGINE key in centreon database options

Fix #4922

www/install/sql/centreon/Update-DB-2.7.8_to_2.7.9.sql

 -- Change version of Centreon
 UPDATE `informations` SET `value` = '2.7.9' WHERE CONVERT( `informations`.`key` USING utf8 )  = 'version' AND CONVERT ( `informations`.`value` USING utf8 ) = '2.7.8' LIMIT 1;
+UPDATE centreon.options SETvalue='CENGINE' WHEREkey='monitoring_engine';