MODE-2066 Migrated to Infinispan 6.0.1 and JGroups 3.4.1. Beside the changes involving package migrations and API changes, because the BDB and JDBM cachestore have not been ported to 6.x yet, all references (only unit tests) to those cache stores were removed and replaced with LevelDB.  The old FileCacheStore has been discontinued and therefore replaced with SingleFileStore.