Enable delete hotkey in web seed and tracker list.

Make delete hotkey in transfer list non-global.

src/properties/trackerlist.h

@@ -54,6 +54,7 @@ private:
   QTreeWidgetItem* pex_item;
   QTreeWidgetItem* lsd_item;
   QShortcut *editHotkey;
+  QShortcut *deleteHotkey;
 
 public:
   TrackerList(PropertiesWidget *properties);