Always backup both certs and kubeconfig

There are no reasons not to backup during upgrade

Signed-off-by: Etienne Champetier <e.champetier@ateme.com>
(cherry picked from commit 53e5ef6b)

Conflicts:
	roles/kubernetes/master/tasks/kubeadm-backup.yml
	roles/kubernetes/master/tasks/kubeadm-certificate.yml