Actually show the tray notification when a torrent finishes downloading.

src/mainwindow.cpp

@@ -528,7 +528,7 @@ void MainWindow::balloonClicked() {
 
 // called when a torrent has finished
 void MainWindow::finishedTorrent(const QTorrentHandle& h) const {
-  if (!TorrentPersistentData::isSeed(h.hash()))
+  if (TorrentPersistentData::isSeed(h.hash()))
     showNotificationBaloon(tr("Download completion"), tr("%1 has finished downloading.", "e.g: xxx.avi has finished downloading.").arg(h.name()));
 }