Normalize the given identifier.
The procedure is described in OpenID Authentication 2.0, section 7.2.
function openid_normalize($identifier) {
$methods = module_invoke_all('openid_normalization_method_info');
drupal_alter('openid_normalization_method_info', $methods);
// Execute each method in turn, stopping after the first method accepted
// the identifier.
foreach ($methods as $method) {
$result = $method($identifier);
if ($result !== NULL) {
$identifier = $result;
break;
}
}
return $identifier;
}