airbnb/stemcell — pull request #57 by sandstrom (2014-07-07 12:34:48+00:00)
Title: Use empty+nil instead of blank, fix issue with gp2 provisioning

- Replaces `blank?` with `empty? || nil?` (Rails ActiveSupport vs. ruby)
- Don't cast `nil` to `0` for `iops`, since the AWS SDK rejects `gp2` provisioning where an `iops` parameter is present.