[Lable] Fix label display name in submenu

Previously every '_' in label's name was incorrectly replaced by '__'

Closes: https://github.com/deluge-torrent/deluge/pull/410

deluge/plugins/Label/deluge_label/gtkui/submenu.py

@@ -51,7 +51,7 @@ class LabelMenu(MenuItem):
             if label == NO_LABEL:
                 item = MenuItem(_(NO_LABEL))  # noqa: F821
             else:
-                item = MenuItem(label.replace('_', '__'))
+                item = MenuItem(label)
             item.connect('activate', self.on_select_label, label)
             self.sub_menu.append(item)
         self.show_all()