Automatic merge from submit-queue

rkt: Fix the 'privileged' check when stage1 annotation is provided.

Previously when stage1 annotation is provided, we only checks if
the kubelet allows privileged, which is not useful as that is a global
setting.

Instead, we should check if the pod has explicitly set the privileged
security context to 'true'.

cc @kubernetes/sig-rktnetes @kubernetes/sig-node