title: InvalidConfigurationException: Unrecognized option "email" under "fos_user.registration"
body: <p>Following the <a href="https://github.com/FriendsOfSymfony/FOSUserBundle/blob/master/Resources/doc/emails.md" rel="nofollow">doc</a>, I still cannot find what is the cause behind the following error:</p>
  
  <pre><code>InvalidConfigurationException: Unrecognized option "email" under "fos_user.registration"
  </code></pre>
  
  <p>My configuration is:</p>
  
  <pre><code>fos_user:
    db_driver: orm
    firewall_name: main
    user_class: Members\Bundle\ManagementBundle\Entity\User
    registration:
          email: 
              template: MembersManagementBundle:Registration:confirmation.html.twig
          confirmation:
              enabled:    true
              from_email:
                  address:        registration@acmedemo.com
                  sender_name:    Acme Demo Registration
    service:
          mailer: fos_user.mailer.twig_swift
    resetting:
      email:
          from_email:
              address:        resetting@acmedemo.com
              sender_name:    Acme Demo Resetting
          template: MembersManagementBundle:Registration:resetting.html.twig
  </code></pre>
  
  <p>I verified indention rules and the template <code>MembersManagementBundle:Registration:confirmation.html.twig</code> physically exists. Additionnaly as you see, template of resetting doesn't create any problem. What could be the things I am missing? Your help is appreciated.</p>