title: 'expires_in' missing from Facebook oauth/access_token response
body: <p>I've just noticed that this method is failing in my ASP.NET web application because I'm not catering for 'expires_in' being missing in the response.</p>
  
  <p>I haven't changed any code recently, and was not aware of any reason for this to be missing in the response. Does this mean that the token has expired?</p>
  
  <p>I'm using version 7.0.6 of the C# Facebook SDK and v2.5 of the Facebook Graph API.</p>
  
  <p>The JSON response looks like this:</p>
  
  <pre><code>{"access_token":"xxxx","token_type":"bearer"}
  </code></pre>