Introduces fix for the cache poisoning issue observed when a node has the next relationship-to-load deleted.

Introduces method TransactionState.patchDeletedRelationshipNodes() which has its concrete implementation
 in NodeManager. That fixes the relChainPosition of affected nodes when they are in cache.
Uses that method when there are relationship deletes, namely in Command application and
 WriteTransaction.prepare()
Un-ignores previously introduced test that reproduced this bug.
Fixes cache poisoning on relationship traversal caused by cache invalidation order

Ensures that WriteTransaction invalidates the cache entries of deleted entities on Command execution
 and not on prepare.
Renames variable in NodeManager.invalidateNode
Unignores test that checks for the issue fixed and removes extraneous System.out and fixes the assertion
 condition to be correct.
Merge pull request #487 from digitalstain/cache-poisoning

Fix for the cache poisoning issue with relationship chain position