chore(*): bump CoreOS to 471.1.0

See https://coreos.com/releases/#471.1.0. In particular, Ceph FS support in the kernel may be important for Deis in the future.

Please double-check alpha IDs at https://coreos.com/docs/running-coreos/cloud-providers/ec2/ and https://coreos.com/docs/running-coreos/cloud-providers/google-compute-engine/