title: GCM unregister causing the application to crash
body: <p>I've implemented GCM notifications on my app. I am now trying to un-register the app when the user logs out. I am using the following code. When this code executes, it causes the application to crash with the following logcat:</p>
  
  <pre><code>java.lang.IllegalAccessError: Method 'void android.support.v4.content.ContextCompat.&lt;init&gt;()' is inaccessible to class 'com.google.android.gms.iid.zzd' (declaration of 'com.google.android.gms.iid.zzd' appears in /data/app/com.example.packagename-1/base.apk)
      at com.google.android.gms.iid.zzd.zzeb(Unknown Source)
      at com.google.android.gms.iid.zzd.&lt;init&gt;(Unknown Source)
      at com.google.android.gms.iid.zzd.&lt;init&gt;(Unknown Source)
      at com.google.android.gms.iid.InstanceID.zza(Unknown Source)
      at com.google.android.gms.iid.InstanceID.getInstance(Unknown Source)
      at com.zaryans.updatedepoultry.WelcomeActivity$11.onItemClick(WelcomeActivity.java:469)
      at android.widget.AdapterView.performItemClick(AdapterView.java:310)
      at android.widget.AbsListView.performItemClick(AbsListView.java:1145)
      at android.widget.AbsListView$PerformClick.run(AbsListView.java:3066)
      at android.widget.AbsListView$3.run(AbsListView.java:3903)
      at android.os.Handler.handleCallback(Handler.java:739)
      at android.os.Handler.dispatchMessage(Handler.java:95)
      at android.os.Looper.loop(Looper.java:148)
      at android.app.ActivityThread.main(ActivityThread.java:5417)
      at java.lang.reflect.Method.invoke(Native Method)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  </code></pre>
  
  <p>Here is the code:</p>
  
  <pre><code>InstanceID instanceID = InstanceID.getInstance(WelcomeActivity.this);
  try {
     instanceID.deleteInstanceID();
     Utility.logCatMsg("Logged Out Success!!!");
  } catch (IOException e) {
     Utility.logCatMsg("Exception while logging out: "+e.getMessage());
     e.printStackTrace();
  }
  </code></pre>