DowntimeQuery: Provide case-insensitive filter column `service_host'

refs #8613

modules/monitoring/library/Monitoring/Backend/Ido/Query/DowntimeQuery.php

@@ -32,6 +32,7 @@ class DowntimeQuery extends IdoQuery
             'host_name'                 => 'CASE WHEN ho.name1 IS NULL THEN so.name1 ELSE ho.name1 END',
             'service'                   => 'so.name2 COLLATE latin1_general_ci',
             'service_description'       => 'so.name2',
+            'service_host'              => 'so.name1 COLLATE latin1_general_ci',
             'service_host_name'         => 'so.name1'
         ),
         'hosts' => array(

modules/monitoring/library/Monitoring/DataView/Downtime.php

@@ -69,6 +69,6 @@ class Downtime extends DataView
 
     public function getFilterColumns()
     {
-        return array('author', 'host', 'service');
+        return array('author', 'host', 'service', 'service_host');
     }
 }