fix issue #1674: AddNewTorrentDialog is shown again and again even if checkbox "dont ask me again" is set

src/mainwindow.cpp

@@ -930,10 +930,9 @@ void MainWindow::on_actionOpen_triggered() {
                                                               tr("Open Torrent Files"), settings.value(QString::fromUtf8("MainWindowLastDir"), QDir::homePath()).toString(),
                                                               tr("Torrent Files")+QString::fromUtf8(" (*.torrent)"));
   if (!pathsList.empty()) {
-    const bool useTorrentAdditionDialog = pref.useAdditionDialog();
     const uint listSize = pathsList.size();
     for (uint i=0; i<listSize; ++i) {
-      if (useTorrentAdditionDialog)
+      if (pref.useAdditionDialog())
         AddNewTorrentDialog::showTorrent(pathsList.at(i));
       else
         QBtSession::instance()->addTorrent(pathsList.at(i));