[licenses] Remove not included dependency from LICENSE

This closes apache#2186

Flink does not include the anchor.js file but loads it dynamically when displaying
the documentation. Therefore, we don't have to include anchor.js in the LICENSE file.

LICENSE

@@ -232,8 +232,7 @@ The Apache Flink project bundles the following files under the MIT License:
  - lodash v3.10.1 (http:https://dojofoundation.org) - Copyright 2012-2015 The Dojo Foundation
  - moment.js v2.10.6 (http:https://momentjs.com/docs/) - Copyright (c) 2011-2014 Tim Wood, Iskren Chernev, Moment.js contributors
  - moment-duration-format v1.3.0 (https://github.com/jsmreese/moment-duration-format) - Copyright (c) 2013 John Madhavan-Reese
- - qtip2 v2.2.1 (http:https://qtip2.com) - Copyright (c) 2012 Craig Michael Thompson
- - AnchorJS (https://github.com/bryanbraun/anchorjs) - Copyright (c) 2013 Craig Michael Thompson
+ - qTip2 v2.2.1 (http:https://qtip2.com) - Copyright (c) 2012 Craig Michael Thompson
 
 All rights reserved.