Fix QFileDialog::viewMode() when using a native file dialog.

It should return the view mode that was set in setViewMode() and
stored in the options.

Change-Id: Iaaa94a201a25baa251446688bf5bdaca5cf3373b
Reviewed-by: Mark Gaiser
Reviewed-by: Dominik Haumann <dhaumann@kde.org>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

src/widgets/dialogs/qfiledialog.cpp

@@ -1600,7 +1600,7 @@ QFileDialog::ViewMode QFileDialog::viewMode() const
 {
     Q_D(const QFileDialog);
     if (!d->usingWidgets())
-        return QFileDialog::List;
+        return static_cast<QFileDialog::ViewMode>(d->options->viewMode());
     return (d->qFileDialogUi->stackedWidget->currentWidget() == d->qFileDialogUi->listView->parent() ? QFileDialog::List : QFileDialog::Detail);
 }