We need to null out this static.

All of the crashes we've been seeing with "Calling RS with no
Context active" were in places that are guarded with if (mRollo != null).

Change-Id: Icb9194cfc4f534bedce5a69a20760a0c3d7fe1d3

src/com/android/launcher2/AllApps3D.java

@@ -204,8 +204,10 @@ public class AllApps3D extends RSSurfaceView
     protected void onDetachedFromWindow() {
         mRS.mMessageCallback = null;
         if (!mSurrendered) {
+            Log.i(TAG, "onDetachedFromWindow");
             destroyRenderScript();
             mRS = null;
+            mRollo = null;
         }
     }