Modify qemuMonitorBlockdevAdd so that it takes a double pointer for the
@props argument so that it's cleared inside the call. This allows
writing cleaner callers.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>