Handles update of peer RT filter.

        Parameters:
            - `peer`: (Peer) whose RT filter has changed.
            - `new_rts`: (set) of new RTs that peer is interested in.
            - `old_rts`: (set) of RTs that peers is no longer interested in.

def _on_update_rt_filter(self, peer, new_rts, old_rts):
        """Handles update of peer RT filter.

        Parameters:
            - `peer`: (Peer) whose RT filter has changed.
            - `new_rts`: (set) of new RTs that peer is interested in.
            - `old_rts`: (set) of RTs that peers is no longer interested in.
        """
        for table in self._table_manager._global_tables.values():
            if table.route_family == RF_RTC_UC:
                continue
            self._spawn('rt_filter_chg_%s' % peer,
                        self._rt_mgr.on_rt_filter_chg_sync_peer,
                        peer, new_rts, old_rts, table)
            LOG.debug('RT Filter change handler launched for route_family %s',
                      table.route_family)