Update usages of http.ResponseWriter.WriteHeader to use http.Error

Signed-off-by: Ibrahim AshShohail <me@ibrasho.com>

pkg/controller/endpoint/endpoints_controller_test.go

@@ -120,7 +120,7 @@ func makeTestServer(t *testing.T, namespace string) (*httptest.Server, *utiltest
 	mux.Handle(testapi.Default.ResourcePath("endpoints/", namespace, ""), &fakeEndpointsHandler)
 	mux.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
 		t.Errorf("unexpected request: %v", req.RequestURI)
-		res.WriteHeader(http.StatusNotFound)
+		http.Error(res, "", http.StatusNotFound)
 	})
 	return httptest.NewServer(mux), &fakeEndpointsHandler
 }

pkg/controller/garbagecollector/dump.go

@@ -252,7 +252,7 @@ type debugHTTPHandler struct {
 
 func (h *debugHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if req.URL.Path != "/graph" {
-		w.WriteHeader(http.StatusNotFound)
+		http.Error(w, "", http.StatusNotFound)
 		return
 	}
 
@@ -270,8 +270,7 @@ func (h *debugHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 
 	data, err := dot.Marshal(graph, "full", "", "  ", false)
 	if err != nil {
-		w.Write([]byte(err.Error()))
-		w.WriteHeader(http.StatusInternalServerError)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 	w.Write(data)