Automatic merge from submit-queue
Guard the ready replica checking by server version
I fixed replica readiness checking for 1.4->1.5 upgrades by using a field that only exists in versions >=1.4.0 in #36924
This fixed a lot of issues in 1.4->1.5 upgrade testing, but did not fix 1.3->1.5 upgrade tests. I've disabled replica checking for 1.3 masters as the old logic was broken anyway.
This will not affect the 1.3 CI tests. Just 1.3 -> {1.4, 1.5} upgrade tests.
https://k8s-gubernator.appspot.com/build/kubernetes-jenkins/logs/kubernetes-e2e-gke-container_vm-1.3-container_vm-1.5-upgrade-cluster-new/330?log
is an example of this breakage. This is the tell-tale logs:
```console
Nov 22 09:40:50.469: INFO: 11 / 11 pods in namespace 'kube-system' are running and ready (506 seconds elapsed)
Nov 22 09:40:50.469: INFO: expected 5 pod replicas in namespace 'kube-system', 0 are Running and Ready.
Nov 22 09:40:50.469: INFO: POD NODE PHASE GRACE CONDITIONS
```
e69b497e07