CHEF-3838 : RabbitMQ does not start on Oracle or Amazon Linux

This is Rob Skaggs workaround to set amazon linux to use upstart instead of sysvinit. I've tested it and it works.

I looked at COOK-2545 but wasn't able to easily get it working as a fix. It looks like using the newer runit cookbook with the fix mentioned in COOK-2545 would require including at least build-essential and yum cookbooks in the omnibus-chef-server which seems like the wrong way to go. If that direction is preferred feel free to close/ignore this PR