LRDOCS-401, Removed instruction to add the
ehcache.cluster.link.replication=true property (this property was wrong,
the correct one is ehcache.cluster.link.replication.enabled=true), clarified and
reorganized the cluster link and distributed caching sections
Merge pull request #415 from jrao/LRDOCS-401

http://issues.liferay.com/browse/LRDOCS-401