Automatic merge from submit-queue

Fix backward compatibility issue caused by promoting initcontainers f…

#31026 moves init-container feature from alpha to beta, but only took care the backward compatibility for pod specification, not deal with status. For status, it simply moved from `pods.beta.kubernetes.io/init-container-statuses` to
`pods.beta.kubernetes.io/init-container-statuses` instead of introducing one more pods.beta.kubernetes.io/init-container-statuses. This breaks when the cluster is running with 1.4, but the user is still running with kubectl 1.3.x. 

Fixed #32711