Hide the "drop" indicator when an item is not hovered any more

This fixes the problem that the drop indicator might still be shown
after the drag&drop operation in the Places Panel is finished.

REVIEW: 111037

src/kitemviews/kitemlistcontroller.cpp

@@ -869,6 +869,8 @@ bool KItemListController::dragMoveEvent(QGraphicsSceneDragDropEvent* event, cons
                 emit itemUnhovered(index);
             }
         }
+    } else {
+        m_view->hideDropIndicator();
     }
 
     return false;