Make cluster autoscaler work with Kubernetes 1.6

[davidopp]

Taints are being moved from annotation to field of Node. See kubernetes/kubernetes#25320 and kubernetes/kubernetes#38957

There's no 1.6 milestone in this repo, but it is needed for 1.6.

[davidopp]

Also, write release notes for any special considerations when upgrading to 1.6.

[davidopp]

cc/ @fgrzadkowski

[kevin-wangzefeng]

/cc @kubernetes/huawei

[davidopp]

#38957 has merged, so HEAD now has the new behavior (taint/toleration annotations are ignored by scheduler, and now scheduler pays attention to taint/toleration fields).

Code freeze is getting close...

[fgrzadkowski]

@mwielgus What's the status of this issue?

[davidopp]

ping @mwielgus -- this is getting pretty urgent

cc/ @kubernetes/release-team

[mwielgus]

CA was done last week. We are polishing couple things/bugfixing before bumping the version in k8s repo.

[mwielgus]

ref #2437