Idempotency fixes (#1838)

library/kube.py

roles/etcd/tasks/main.yml

...s/kubernetes-apps/policy_controller/calico/tasks/main.yml

roles/kubernetes/master/tasks/main.yml

roles/kubernetes/master/tasks/pre-upgrade.yml

roles/kubernetes/node/tasks/facts.yml

roles/kubernetes/node/tasks/pre_upgrade.yml

roles/network_plugin/calico/tasks/main.yml

roles/network_plugin/canal/tasks/main.yml