title: Google plus login access token retriew issue
body: <p>I have integrated google plus login in to my android application according to the following link </p>
  
  <p><a href="https://developers.google.com/+/quickstart/android" rel="nofollow">google plus andoid integration </a></p>
  
  <p>But now I want to retrieve the access token, for that I have created a project in api console and developed a client id for android application, </p>
  
  <p>This is how I retrieve the token. but unfortunately I can't get the token, it recieves null</p>
  
  <pre><code>String scopesString = Scopes.PLUS_LOGIN + " " + Scopes.PLUS_ME;
  String scopes = "oauth2:server:client_id:" + "client id" + ":api_scope:" + scopesString;
  </code></pre>
  
  <p>also there is an exception </p>
  
  <pre><code>03-17 15:20:14.338: W/System.err(8084): com.google.android.gms.auth.GoogleAuthException: Unknown
  03-17 15:20:14.338: W/System.err(8084):     at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source)
  03-17 15:20:14.338: W/System.err(8084):     at com.myapp.exemple.NewInstallation$12.doInBackground(NewInstallation.java:600)
  03-17 15:20:14.338: W/System.err(8084):     at com.myapp.exemple.NewInstallation$12.doInBackground(NewInstallation.java:1)
  03-17 15:20:14.348: W/System.err(8084):     at android.os.AsyncTask$2.call(AsyncTask.java:264)
  03-17 15:20:14.348: W/System.err(8084):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
  03-17 15:20:14.348: W/System.err(8084):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
  03-17 15:20:14.348: W/System.err(8084):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
  03-17 15:20:14.348: W/System.err(8084):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
  03-17 15:20:14.348: W/System.err(8084):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
  03-17 15:20:14.348: W/System.err(8084):     at java.lang.Thread.run(Thread.java:856)
  </code></pre>