Fix bug where realtimeReorder is called after views have been unbound.

Bug: 161498651
Change-Id: I89beaad9a91bfa1763454965bf95ba1a94d29902

src/com/android/launcher3/folder/FolderPagedView.java

@@ -500,6 +500,9 @@ public class FolderPagedView extends PagedView<PageIndicatorDots> {
      * Reorders the items such that the {@param empty} spot moves to {@param target}
      */
     public void realTimeReorder(int empty, int target) {
+        if (!mViewsBound) {
+            return;
+        }
         completePendingPageChanges();
         int delay = 0;
         float delayAmount = START_VIEW_REORDER_DELAY;