net/http: use t.Fatalf rather than t.Fatal in cookie_test.go

Change-Id: I60bbb7deb7462d1ca884677b4f86bd54b20b3f35
Reviewed-on: https://go-review.googlesource.com/2140Reviewed-by: Minux Ma <minux@golang.org>

src/net/http/cookie_test.go

@@ -349,7 +349,7 @@ func TestSetCookieDoubleQuotes(t *testing.T) {
 		{Name: "quoted3", Value: "both"},
 	}
 	if len(got) != len(want) {
-		t.Fatal("got %d cookies, want %d", len(got), len(want))
+		t.Fatalf("got %d cookies, want %d", len(got), len(want))
 	}
 	for i, w := range want {
 		g := got[i]