ISPN-2784 ReplStateTransferCacheLoaderTest fails randomly in FileCacheStore.start()

This failure seems platform related. Will use the same approach to create the temp dir as in FileCacheStoreTest.
Test was missing assert statement
ISPN-2803 Ensure the updatedKeys set doesn't get reinitialized erroneously when state transfer completes.
ISPN-2804 Added executor to clean up the completed transaction table.
Slight cleanup

* Javadoc for getNormalizedHash() in Util and ConsistentHash
* Remove redundant "normalization" checks in ConsistentHashV1.getServer()
Updated versions to 5.2.1-SNAPSHOT
ISPN-2800 Make sure the JDBC XSD refers to simpleConnection and not singleConnection
ISPN-2658 Fix expected value MarshalledValueTest.testModificationsOnSameCustomKey

After fixing ISPN-2803 the key is not added in StateConsumerImpl.updatedKeys so no extra comparison (and serialization) is done. Decrease expected value by 1.
ISPN-2794 Stop the CacheManager when the servlet context is destroyed
ISPN-2795 JGroups 3.2.7.Final