Update to 0.99.23.1.

Remove a patch which has been incorporated upstream, and one which has
been superceded.

Add a patch to use the system's RT_ROUNDUP macro if defined,
which fixes IPv6 routing on NetBSD 6 (where rtsock alignment has
changed).

Upstream NEWS:

* Changes in Quagga 0.99.23

Known issues:
- [bgpd] setting an extcommunity in a route map on a route that already has
  an extcommunity attribute will cause bgpd to crash.  This issue will be
  fixed in a followup minor release.

User-visible changes:
- [lib] Performance enhancements on hashes and timers.
- [bgpd] New feature: iBGP TTL security.
- [bgpd] New feature: relaxed bestpath criteria for multipath and improved
  display of multipath routes in "show ip bgp".  Scripts parsing this output
  may need to be updated.
- [bgpd] Multiprotocol peerings over IPv6 now try to find a more appropriate
  IPv4 nexthop by looking at the interface.
- [ospf6d] A large amount of changes has been merged for ospf6d.  Careful
  evaluation prior to deployment is recommended.
- [zebra] Recursive route support has been overhauled.  Scripts parsing
  "show ip route" output may need adaptation.
- [zebra] IPv6 address management has been improved regarding tentative
  addresses.  This is visible in that a freshly configured address will not
  immediately be marked as usable.
- [*] a lot of bugs have been fixed, please refer to the git log

(gdt)