(PUP-3010) Allow Upstart jobs on Amazon Linux

Amazon Linux is a RedHat derivative and comes with support for Upstart built in.  The current Upstart requirements assume the RedHat versioning scheme, but Amazon Linux does not use the same versioning scheme.

This change allows the use of Upstart jobs on Amazon linux.
I'm not sure how I can find that out.  We could restrict to a specific version of Amazon Linux if we knew that they were sunsetting support.