Determine if URL is a local.

def is_local_url(target):
    """Determine if URL is a local."""
    ref_url = urlparse(cfg.get('CFG_SITE_SECURE_URL'))
    test_url = urlparse(urljoin(cfg.get('CFG_SITE_SECURE_URL'), target))
    return test_url.scheme in ('http', 'https') and \
        ref_url.netloc == test_url.netloc