QUrl::removeQueryItem leaves dangling questionmark

The following little test case shows the bug:

QUrl url("http://www.foobar.com/");
QUrl url1(url);
url1.addQueryItem(QLatin1String("foo"), QLatin1String("bar"));
QUrl url2(url1);
QUrl url3(url2);

url1.removeQueryItem(QLatin1String("foo"));
QCOMPARE(url, url1);

url3.addQueryItem(QLatin1String("foo2"), QLatin1String("bar2"));
url3.removeQueryItem(QLatin1String("foo2"));
QCOMPARE(url2, url3);