Read existing local.conf and strip out service id and client secret
    :param config: Location of config files
    :param lines of existing config (excluding service id and client secret)

def _get_existing_conf(config):
    """
    Read existing local.conf and strip out service id and client secret
    :param config: Location of config files
    :param lines of existing config (excluding service id and client secret)
    """
    try:
        with open(os.path.join(config, 'local.conf'), 'r') as f:
            lines = [line for line in f.readlines()
                     if not (line.startswith('service_id') or line.startswith('client_secret'))]
    except IOError:
        lines = []
    return lines