As specified in:
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/command/irg-cr-book/bgp-m1.html#wp4972925610
This allows overriding next-hop for ibgp learned routes on an
RR for reflected routes.
Especially useful for using iBGP in DMVPN setups. See:
http://blog.ipspace.net/2014/04/changes-in-ibgp-next-hop-processing.html
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
