user_login_submit is inflexible and documentation is misleading

http://api.drupal.org/api/function/hook_user_login/7 suggest that &$edit is the $form_state that gets passed to hook_user_login, however it doesn't. here is patch for that.

Also i changed order of $form_state and user_login_finalize, giving chance to other modules alter where user gets redirected on login.