title: GCMRegistrar.onDestroy(context) crashing, Receiver not registered
body: <p>How should I call GCMRegistrar.onDestroy? Currently my main activity contains this: </p>
  
  <pre><code>protected void onDestroy() {
      GCMRegistrar.onDestroy(this);
      super.onDestroy();
  }
  </code></pre>
  
  <p>And after doing a registration or unregistration and then killing the main activity I am getting this:</p>
  
  <pre><code>08-13 15:43:56.459: E/AndroidRuntime(2389): FATAL EXCEPTION: main
  08-13 15:43:56.459: E/AndroidRuntime(2389): java.lang.RuntimeException: Unable to destroy activity {com.test.android/com.test.android.activities.MainActivity}: java.lang.IllegalArgumentException: Receiver not registered: com.google.android.gcm.GCMBroadcastReceiver@40673a10
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3090)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3155)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread.access$2100(ActivityThread.java:132)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1071)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.os.Handler.dispatchMessage(Handler.java:99)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.os.Looper.loop(Looper.java:150)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread.main(ActivityThread.java:4277)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at java.lang.reflect.Method.invokeNative(Native Method)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at java.lang.reflect.Method.invoke(Method.java:507)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at dalvik.system.NativeStart.main(Native Method)
  08-13 15:43:56.459: E/AndroidRuntime(2389): Caused by: java.lang.IllegalArgumentException: Receiver not registered: com.google.android.gcm.GCMBroadcastReceiver@40673a10
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:634)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:880)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.content.Contexttester.unregisterReceiver(Contexttester.java:331)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at com.google.android.gcm.GCMRegistrar.onDestroy(GCMRegistrar.java:249)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at com.test.android.activities.MainActivity.onDestroy(MainActivity.java:407)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3072)
  08-13 15:43:56.459: E/AndroidRuntime(2389):     ... 11 more
  </code></pre>
  
  <p>Edit, from the mainfest:</p>
  
  <pre><code>&lt;receiver android:name=".receivers.PushReceiver"
    android:permission="com.google.android.c2dm.permission.SEND" &gt;
    &lt;intent-filter&gt;
      &lt;action android:name="com.google.android.c2dm.intent.RECEIVE" /&gt;
      &lt;action android:name="com.google.android.c2dm.intent.REGISTRATION" /&gt;
  
      &lt;category android:name="com.test.android" /&gt;
    &lt;/intent-filter&gt;
  &lt;/receiver&gt;
  
  &lt;service android:name=".services.PushService" /&gt;
  </code></pre>