/etc/ec2_version exists in non-ec2 images

[dann frazier]

/etc/ec2_version appears to be present in all of our cloud images. I would only expect to see it in EC2 images. For example:

https://cloud-images.ubuntu.com/focal/20221031/focal-server-cloudimg-amd64.img

[Thomas Bechtold (toabctl)]

This is done for all CPC images in https://git.launchpad.net/livecd-rootfs/tree/live-build/ubuntu-cpc/hooks.d/chroot/010-write-etc-ec2-version.chroot .

[dann frazier (dannf)]

This causes a problem for a user who is checking for this file to determine whether or not they are running in EC2 vs. bare metal. AIUI, this assumption was made while using a non-cloud-image install method (d-i/bionic maybe?) on bare metal. The user has now moved to a cloud-image-based install type for bare metal, thus breaking their assumption. So while it isn't a cloud image regression (this isn't new) and while the meaning of this file's presence is not defined, it is arguably a regression between these install methods.