docker/machine — pull request #98 by ehazlett (2014-12-13 01:34:30+00:00)
Title: use vpc-id and zone instead of subnet-id for ec2

This removes the `subnet-id` option in favor of `vpc-id` and `zone`. This is more practical for the end user. For example, instead of digging for a subnet id, simply specify a vpc-id and zone (such as `vpc-0d2344` and `a`).