Auto promote on green build
Auto promote on green build

[#105489488](https://www.pivotaltracker.com/story/show/105489488)

Signed-off-by: Edwin Xie <6bc24e9c160281972837d9e13287696d26612564@pivotal.io>

pivotal-golang/s3cli,pivotal-golang/s3cli,pivotal-golang/s3cli,pivotal-golang/s3cli