Log Message:
Update to 0.99.21

* Changes in Quagga 0.99.21

- [bgpd] BGP multipath support has been merged
- [bgpd] SAFI (Multicast topology) support has been extended to propagate
  the topology to zebra.
- [bgpd] AS path limit functionality has been removed
- [babeld] a new routing daemon implementing the BABEL ad-hoc mesh routing
  protocol has been merged.
- [isisd] a major overhaul has been picked up. Please note that isisd is
  STILL NOT SUITABLE FOR PRODUCTION USE.
- [*] a lot of bugs have been fixed, please refer to the git log