Add missing UID in SubjectAccessReviewSpec

WebhookAuthorizer's Authorize should send *all* the information
present in the user.Info data structure. We are not sending the
UID currently.

Kubernetes-commit: 9a761b16c1558106800222dbc52f6ab03c40c64c

plugin/pkg/authorizer/webhook/webhook.go

@@ -144,6 +144,7 @@ func (w *WebhookAuthorizer) Authorize(attr authorizer.Attributes) (authorized bo
 	if user := attr.GetUser(); user != nil {
 		r.Spec = authorization.SubjectAccessReviewSpec{
 			User:   user.GetName(),
+			UID:    user.GetUID(),
 			Groups: user.GetGroups(),
 			Extra:  convertToSARExtra(user.GetExtra()),
 		}

plugin/pkg/authorizer/webhook/webhook_test.go

@@ -505,6 +505,7 @@ func TestWebhook(t *testing.T) {
 				TypeMeta: expTypeMeta,
 				Spec: v1beta1.SubjectAccessReviewSpec{
 					User:   "jane",
+					UID:    "1",
 					Groups: []string{"group1", "group2"},
 					ResourceAttributes: &v1beta1.ResourceAttributes{
 						Verb:        "GET",