This change stops to update status in CNI's DEL command.
There are two reasons:
1. cmd DEL is invoked at only pod deletion, hence k8s does not
guarantee the pod and it may be already deleted. Hence this
API may failed.
2. In stateful set's pod recreation case, it may have race
condition to update the status at cmd DEL case.
In stateful set case, same pod name, i.e. stateful-0, is deleted
and then created again. In this case, if old Pod's CNI DEL command
is not finished before new Pod's creation, then SetStatus function
is failed due to pod UID mismatch.
This change introduces per-node certification for multus pods.
Once multus pod is launched, then specified bootstrap kubeconfig
is used for initial access, then multus sends CSR request to
kube API to get original certs for kube API access. Once it is
accepted then the multus pod uses generated certs for kube access.
