ec2-init: RightScale startup script removes itself

The ec2-init package includes a startup script in /etc/init.d/rightscale which checks to see if the instance was started from with in a RightScale environment.

In either case, this script removes itself. There are a couple issues with this:

1. It is unexpected and possibly a bit threatening to have an AMI run code on startup which is then removed before the user is given a chance to log in and see it. It is impossible for a user to view the source of the AMI before running it, so there is no way to verify what code is being run on the instance. This can be a cause of concern, especially if it is a publisher's known practice to delete startup code.

2. If a user runs an instance of the AMI and rebundles the instance as a new AMI, that new AMI no longer has support for being run inside RightScale with startup hooks.

A more appropriate approach for RightScale startup code would be to check and install the software on the first boot of each instance/AMI. Once the software gets installed, the script could disable (but not remove) itself.