flannel: Kubernetes 1.12 and flannel does not work out of the box

Seems like a new behavior with kubeadm, after I created a master, I see two taints on the master node:

Taints:             node-role.kubernetes.io/master:NoSchedule
                    node.kubernetes.io/not-ready:NoSchedule

But https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml has toleration only to

- key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule

I added a toleration to kube-flannel.yml to solve the issue:

      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      - key: node.kubernetes.io/not-ready
        operator: Exists
        effect: NoSchedule

Expected Behavior

The docs should work with flannel out of the box https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/

Current Behavior

Possible Solution

Maybe instead it should use a toleration without a key?

tolerations:
        - effect: NoSchedule
          operator: Exists

Steps to Reproduce (for bugs)

1. Bootstrap master node with kubeadm
2. Apply as suggested https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml from the docs.

Context

Your Environment

• Flannel version: v0.10.0
• Backend used (e.g. vxlan or udp):
• Etcd version:
• Kubernetes version (if used): 1.12
• Operating System and version: Linux master1 4.4.0-134-generic #160-Ubuntu SMP Wed Aug 15 14:58:00 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux, "Ubuntu 16.04.5 LTS"
• Link to your project (optional):