builder="hvm" is deprecated since Xen 4.10, new syntax is type="hvm" (or
type="pv", which is default). Since the old one is still supported,
still use it when writing native config, so the config will work on
older Xen too (and will also not complicate tests).
Signed-off-by: NMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: NJim Fehlig <jfehlig@suse.com>