Contiv IPV6 support

[blaksmit]

From Rohit Agarwalla. Details needed.

"FYI…I think if Contiv CNI supported IPv6 with this work then it’ll be a good value add."

From Daneyon:
Rohit/Pradeep,

Dane Leblanc from the cloud-c2 team has created a Kubernetes IPv6 deployment guide [1]. The guide will be transitioned into upstream Kubernetes documentation for the 1.9 release. Feel free to use the guide for your test/dev efforts. We would appreciate any feedback you may have.

[1] https://github.com/leblancd/kube-v6

[CIR-2106] created by blaksmit