Fix bug 4678 (Clicking on a Nautilus link file in tree view causes
	Nautilus cannot handle item type error box).

	* components/tree/nautilus-tree-view.c:
	(nautilus_tree_view_destroy), (got_activation_uri_callback),
	(cancel_possible_activation), (tree_select_row_callback): Activate
	activation URI instead of file URI to support Nautilus links
	properly. If the link resolves to a "command:" URI, however,
	silently ignore it to avoid giving an ugly error message because
	per John Sullivan, selecting things in the tree view should not
	launch apps.

	* components/tree/nautilus-tree-view-private.h: Added
	activation_uri_wait_file field to details struct.

	* data/top/Computer, data/top/Services: Updated to new nautilus
	link format.