Feature Request: Add support for amazonlinux

Converging on Amazon Linux, whose base OS is Centos, poise-service uses Upstart as the provider. Since it doesn't recognize the OS it fails the converge on service start.

start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused

Tested with Chef 12.11.18 on latext amazonlinux Docker container using kitchen-docker