Before the `kops validate cluster` attempts to connect to the K8s API
endpoint, the code now checks to see if the API DNS Entry is the kops
placeholder IP Address 203.0.113.123. It prints a message to the user
and err's. There is a new init func in validate cluster that disables
CGO based DNS for Darwin OS. Darwin does two things with kops
validates; it caches the IP address, and it does not return the
placeholder IP address. We cannot use CGO base DNS with kops validate.