Introduce an internal schema for a single device and use it to test the
various files in tests/qemuhotplugtestdevices and
tests/qemublocktestdata directories.
This also requires us to implement schema for (some) privateData bits
for the disk source.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
