be used on HVM instances without needing nixops. Previously
the grub setup was incorrect, so a plain 'nixos-rebuild switch'
and a reboot would result in a broken system.
Also added growing of the partition of the root disk in the initrd,
so you can run resize2fs after initial boot, without needing an
extra reboot. This is useful especially for nixops'
deployment.ec2.ebsInitialRootDiskSize option.
(cherry picked from commit 044a24e58bcf4cf48df02df936c542839fb08d90)
* Use smaller instances to generate HVM images
* Use HVM base image that has 4 ephemeral disks in device mapping
* As grub is not on the base images anymore, install it first before copying parts of its contents
