Allow modules to modify the OpenID request parameters.
$request: An associative array of request parameters.
$service: A service array as returned by openid_discovery().
function hook_openid_request_alter(&$request, $service) {
if ($request['openid.mode'] == 'checkid_setup') {
$request['openid.identity'] = 'http://myname.myopenid.com/';
}
}