func (ref ostreeReference) signaturePath(index int) string {
	return filepath.Join("manifest", fmt.Sprintf("signature-%d", index+1))
}
func (ref ostreeReference) signaturePath(index int) string {
	return filepath.Join("manifest", fmt.Sprintf("signature-%d", index+1))
}
// signaturePath returns a path for a signature within a ostree using our conventions.