[GTKUI|Py3] Ensure backward compatible pickle dumps

deluge/core/torrentmanager.py

@@ -861,7 +861,7 @@ class TorrentManager(component.Component):
         try:
             log.debug('Creating the temporary file: %s', filepath_tmp)
             with open(filepath_tmp, 'wb', 0) as _file:
-                pickle.dump(state, _file)
+                pickle.dump(state, _file, protocol=2)
                 _file.flush()
                 os.fsync(_file.fileno())
         except (OSError, pickle.PicklingError) as ex:

deluge/ui/gtkui/common.py

@@ -264,7 +264,7 @@ def save_pickled_state_file(filename, state):
         try:
             with open(filepath_tmp, 'wb') as _file:
                 # Pickle the state object
-                pickle.dump(state, _file)
+                pickle.dump(state, _file, protocol=2)
                 _file.flush()
                 os.fsync(_file.fileno())
             shutil.move(filepath_tmp, filepath)

deluge/ui/gtkui/files_tab.py

@@ -757,7 +757,7 @@ class FilesTab(Tab):
 
     def _on_drag_data_get_data(self, treeview, context, selection, target_id, etime):
         paths = self.listview.get_selection().get_selected_rows()[1]
-        selection.set_text(pickle.dumps(paths))
+        selection.set_text(pickle.dumps(paths, protocol=2))
 
     def _on_drag_data_received_data(self, treeview, context, x, y, selection, info, etime):
         try: