onDropChild() always marks the cell as occupied.

Bug: 24164487
Change-Id: I11ef638a56b638ee82c3cd748340995970fc7e32

src/com/android/launcher3/CellLayout.java

@@ -2667,6 +2667,7 @@ public class CellLayout extends ViewGroup implements BubbleTextShadowHandler {
             LayoutParams lp = (LayoutParams) child.getLayoutParams();
             lp.dropped = true;
             child.requestLayout();
+            markCellsAsOccupiedForView(child);
         }
     }