grab directory path from named{conf,boot}

def get_dns_dir(self, config_file):
        """ grab directory path from named{conf,boot}
        """
        directory_list = self.do_regex_find_all(r"directory\s+\"(.*)\"",
                                                config_file)
        if directory_list:
            return normpath(directory_list[0])
        else:
            return ""