fixes #2393 clusterzone check is not a plugincheck (#2502)

Author: lippserd

library/Director/Objects/IcingaCommand.php

@@ -61,7 +61,7 @@ class IcingaCommand extends IcingaObject implements ObjectWithArguments, ExportI
         // Special, internal:
         'IcingaCheck'      => 'icinga-check-command',
         'ClusterCheck'     => 'cluster-check-command',
-        'ClusterZoneCheck' => 'plugin-check-command',
+        'ClusterZoneCheck' => 'cluster-zone-check-command',
         'IdoCheck'         => 'ido-check-command',
         'RandomCheck'      => 'random-check-command',
     ];