Improve static resource path check

(cherry picked from commit 2697425)

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 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.
@@ -281,7 +281,7 @@ public class ResourceHttpRequestHandler extends WebContentGenerator implements H
 				return true;
 			}
 		}
-		if (path.contains("../")) {
+		if (path.contains("..")) {
 			path = StringUtils.cleanPath(path);
 			if (path.contains("../")) {
 				if (logger.isTraceEnabled()) {