Use controller interface for everything in config factory

plugin/pkg/scheduler/factory/factory.go

@@ -80,12 +80,12 @@ type ConfigFactory struct {
 	StopEverything chan struct{}
 
 	informerFactory       informers.SharedInformerFactory
-	scheduledPodPopulator *cache.Controller
-	nodePopulator         *cache.Controller
-	pvPopulator           *cache.Controller
+	scheduledPodPopulator cache.ControllerInterface
+	nodePopulator         cache.ControllerInterface
+	pvPopulator           cache.ControllerInterface
 	pvcPopulator          cache.ControllerInterface
-	servicePopulator      *cache.Controller
-	controllerPopulator   *cache.Controller
+	servicePopulator      cache.ControllerInterface
+	controllerPopulator   cache.ControllerInterface
 
 	schedulerCache schedulercache.Cache