Fixes on updates on the PredictionRowView

> resetup header if content switches from empty to non-empty
> scroll to top on reset

Change-Id: Idc523a94990e9a8f9d639485fa5c7ec60eb378de

src/com/android/launcher3/allapps/FloatingHeaderView.java

@@ -176,6 +176,7 @@ public class FloatingHeaderView extends RelativeLayout implements
         mAnimator.start();
         mHeaderCollapsed = false;
         mSnappedScrolledY = -mMaxTranslation;
+        mCurrentRV.scrollToTop();
     }
 
     public boolean isExpanded() {