if the deleted node was "below" this path, then do not unref all nodes

if the deleted node was "below" this path, then do not unref all nodes

Fri Apr 26 21:58:16 2002  Kristian Rietveld  <kris@gtk.org>

        * gtk/gtktreemodel.c (gtk_tree_row_ref_deleted_callback): if the
        deleted node was "below" this path, then do not unref all nodes
        between the deleted parent and the node this rowref is pointing too
        (see added comment in gtk_tree_row_ref_deleted_callback),
        (fixes #77977)