Fix tests for DragDropContainer

Author: conor-j-malone

src/addons/draggable/Container.js renamed to src/addons/draggable/DragDropContainer.js

@@ -1,4 +1,4 @@
-import Container from './Container';
+import Container from './DragDropContainer';
 import DraggableHeaderCell from './DraggableHeaderCell';
 import RowActionsCell from './RowActionsCell';
 import DropTargetRowContainer from './DropTargetRowContainer';