Use Real CoreOS on DigitalOcean

Note: this won't work. DigitalOceans CoreOS is too new for current deis version...

Howto Test Provisioning:

* edit contrib/coreos/user-data as usual to include your new discovery URL
* `gem install barge`
* `cd contrib/digitalocean`
* Create a personal Access Token on DO (https://cloud.digitalocean.com/settings/applications)
* Copy the token a new file to do-access-token (in contrib/digitalocean)
* exectue ./provision-do-cluster.sh lon1 230790 2GB
Replace the middle value with your SSH ID
The first value is identifier for the region (valid values are sfo1 lon1 ny3).
Last value is the size identifier in the form of NGB (eg 8GB which used to be the default)
* Wait & look for the IP on the DO website in your droplet list
* `ssh core@$PUBLICIP`
* This show show welcome to DEIS
$ `fleetctl list-machines
Should list the 3 machines provided (or more if you modified DEIS_NUM_INSTANCES)
I think we need to add a check to see if the image has been found or not. It sends region name as user_data path if image cannot be found (due to order of args)