fix login page redirect error

There is an error with current version. Example:
If `GET /login?redirect=%2Foauth2%2Fauth%3Fresponse_type%3Dcode%26client_id%3Dcli`, `Login.getLogin` will generate a html page with a form, whose `action` is `POST /login?redirect=/oauth2/auth?response_type=code&client_id=cli`. This action is incorrect without encodeURIComponent.