AbstractXlsView does not explicitly flush (for compatibility with WebSphere Liberty)

Issue: SPR-13910

spring-webmvc/src/main/java/org/springframework/web/servlet/view/document/AbstractXlsView.java

 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -98,7 +98,6 @@ public abstract class AbstractXlsView extends AbstractView {
 	protected void renderWorkbook(Workbook workbook, HttpServletResponse response) throws IOException {
 		ServletOutputStream out = response.getOutputStream();
 		workbook.write(out);
-		out.flush();
 
 		// Closeable only implemented as of POI 3.10
 		if (workbook instanceof Closeable) {