Pressing Locations hotkey in Trash list results in exception

[joshas]

While Trash list does not have "Locations" button, pressing hotkey Ctrl+F1 (or F2, depending on panel) results in exception:

Traceback (most recent call last):
  File "/home/virtualbox/dev/Sunflower/sunflower/accelerator_group.py", line 93, in _handle_activate
    result = callback_method(widget, label)
  File "/home/virtualbox/dev/Sunflower/sunflower/plugin_base/item_list.py", line 344, in _show_left_bookmarks
    self._parent.show_bookmarks_menu(None, self._parent.left_notebook)
  File "/home/virtualbox/dev/Sunflower/sunflower/gui/main_window.py", line 1536, in show_bookmarks_menu
    reference = target_object.locations_button
AttributeError: 'TrashList' object has no attribute 'locations_button'

[MeanEYE]

Ah, yes. Trash list is based on ItemList, so I assumed locations button will be present everywhere. This needs to safely fall back to an acceptable solution. It would be weird if we didn't show popover when user requested it.