Remove any relationship that contain user-specified edges.

def _rm_gos_edges_rel(self, rm_goids, edges_rel):
        """Remove any relationship that contain user-specified edges."""
        edges_ret = {}
        for rname, edges_cur in edges_rel.items():
            edges_new = self._rm_gos_edges(rm_goids, edges_cur)
            if edges_new:
                edges_ret[rname] = edges_new
        return edges_ret