admission: make metrics compositional and move to metrics sub-package

plugin/pkg/admission/namespace/autoprovision/admission_test.go

@@ -136,7 +136,7 @@ func TestIgnoreAdmission(t *testing.T) {
 		t.Errorf("unexpected error initializing handler: %v", err)
 	}
 	informerFactory.Start(wait.NeverStop)
-	chainHandler := admission.NewChainHandler(admission.NewNamedHandler("ns", handler))
+	chainHandler := admission.NewChainHandler(handler)
 
 	pod := newPod(namespace)
 	err = chainHandler.Admit(admission.NewAttributesRecord(&pod, nil, api.Kind("Pod").WithVersion("version"), pod.Namespace, pod.Name, api.Resource("pods").WithVersion("version"), "", admission.Update, nil))

plugin/pkg/admission/persistentvolume/label/admission_test.go

@@ -78,7 +78,7 @@ func mockVolumeLabels(labels map[string]string) *mockVolumes {
 // TestAdmission
 func TestAdmission(t *testing.T) {
 	pvHandler := NewPersistentVolumeLabel()
-	handler := admission.NewChainHandler(admission.NewNamedHandler("pv", pvHandler))
+	handler := admission.NewChainHandler(pvHandler)
 	ignoredPV := api.PersistentVolume{
 		ObjectMeta: metav1.ObjectMeta{Name: "noncloud", Namespace: "myns"},
 		Spec: api.PersistentVolumeSpec{