test,util/packer: Add ZFS to vm images.

Signed-off-by: Eric Myhre <eric@flynn.io>
test,util/packer: Describe each apt key as they are registered in bootstrap scripts.

Signed-off-by: Eric Myhre <eric@flynn.io>
Merge pull request #625 from flynn/add-zfs-to-vm-images

Add ZFS to vm images.