During initialization `kubeadm init` creates kubelet.conf with
specified name and during finalize phase validates that
this kubeconfig is not corrupted by checking for presence of specific
authinfo
However:
* kubelet doesn't require a specific name for this context
* in external CA mode this kubeconfig can be created outside of
`kubeadm init`
This change updates kubeadm finalize stage to avoid overly strict
context check.
fc610f0941