Issues fixed:
Output of kernel, init and inithooks correctly displayed in console.
SystemD working again.
Root disk is grown to match flavor size; done without reboot.
Kernel updates possible.

Old AMI version retained as openstack-ami.

This change removes all ec2 user data functionality from inithooks
and relies on cloud-init for that.

Inithooks init scripts are made to depend on cloud-init's cloud-config parsing.

User data may be in #cloud-config format or a #!/bin/bash script, meaning that
e.g. user creation can be done in cloud-init, or you can change passwords
by inithooks preseeding, possibly both using cloud-init's "write file".

Turnkey-init-fence script now covers all possible created user accounts.
Turnkey-sudoadmin is made obsolete, at least in this build.

All bugs should remain fixed, as in the last pull request.

Possible caveats:
Turnkey-init-fence runs later in the boot process.

Root password login works on the VNC console AND through ssh. Is it a problem?
Cloud-init's settings to disable it get overwritten by inithooks.

Did I break something related to the Hub? I believe not, at least directly,
as the functionality is absent from non-EC2 builds.
It's not as important now, but once we integrate it with OpenStack...

Modified bootloader and fstab to work with both /dev/sda1 and /dev/vda1.