Since most property types do not have a parse property now, this was
broken.  Fix it by looking at the setter instead.
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
Acked-by: NAndreas F=E4rber <afaerber@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>