Build a /-separated string from an x509.Name.

def _name_attribute_to_string(self, name):
        """
        Build a /-separated string from an x509.Name.
        """
        return "".join(
            "/{}={}".format(
                self._get_oid_name(attr.oid),
                attr.value,
            )
            for attr in name
        )