kubelet: Make service environment variables optional

pkg/api/testing/serialization_test.go

@@ -214,6 +214,7 @@ func TestRoundTripTypes(t *testing.T) {
 // decoded without information loss or mutation.
 func TestEncodePtr(t *testing.T) {
 	grace := int64(30)
+	enableServiceLinks := api.DefaultEnableServiceLinks
 	pod := &api.Pod{
 		ObjectMeta: metav1.ObjectMeta{
 			Labels: map[string]string{"name": "foo"},
@@ -224,8 +225,9 @@ func TestEncodePtr(t *testing.T) {
 
 			TerminationGracePeriodSeconds: &grace,
 
-			SecurityContext: &api.PodSecurityContext{},
-			SchedulerName:   api.DefaultSchedulerName,
+			SecurityContext:    &api.PodSecurityContext{},
+			SchedulerName:      api.DefaultSchedulerName,
+			EnableServiceLinks: &enableServiceLinks,
 		},
 	}
 	obj := runtime.Object(pod)