Fix failed test

cmd/helm/repo_update_test.go

@@ -46,10 +46,11 @@ func TestUpdateCmd(t *testing.T) {
 	out := bytes.NewBuffer(nil)
 	// Instead of using the HTTP updater, we provide our own for this test.
 	// The TestUpdateCharts test verifies the HTTP behavior independently.
-	updater := func(repos []*repo.ChartRepository, out io.Writer, hh helmpath.Home) {
+	updater := func(repos []*repo.ChartRepository, out io.Writer, hh helmpath.Home) error {
 		for _, re := range repos {
 			fmt.Fprintln(out, re.Config.Name)
 		}
+		return nil
 	}
 	uc := &repoUpdateCmd{
 		update: updater,