title: spring social get user email while authenticate
body: <p>We are using spring-social to integrate our application to facebook.
  In OAuth2AuthenticationService, scope is empty.
  We set scope as a input on form.But it was not work and scope could not be set . 
  We could not get user email.</p>
  
  <p>Are there any way to override "OAuth2AuthenticationService" scope variable ?</p>
  
  <p>Not: Spring social verison is 1.1.0.BUILD-SNAPSHOT</p>
  
  <p><a href="https://github.com/SpringSource/spring-social-samples/tree/master/spring-social-showcase-xml" rel="nofollow">We used spring social sample which contains security xml version</a></p>
  
  <pre><code>            &lt;form name="fb_signin" id="fb_signin" action="../auth/facebook"
                  method="post"&gt;
                  &lt;input type="hidden" name="scope"
                      value="email,publish_stream,read_stream,offline_access" /&gt; 
                  &lt;button type="submit"&gt; &lt;img src="../images/social/facebook/sign-in-with-facebook.png" /&gt; &lt;/button&gt;  
                  &lt;!--  
                  &lt;input
                      type="image"
                      src="../images/social/facebook/sign-in-with-facebook.png"
                      align="right" /&gt;
                  --&gt; 
              &lt;/form&gt;
  </code></pre>