ISPN-2754 Fix the infinispan-config-5.2.xsd schema to allow multiple "external" stores (i.e. declared in other schemas)
ISPN-2647 ReplaceCommand does not perform any modifications if the entry was not yet transfered during rehashing

Fixes distributed case only. The replicated case still fails, so the test is still disabled.

* Add more trace logging
* Extend consistency tests to also cover putIfAbsent
* TxDistributionInterceptor will do a remoteGetBeforeWrite() if the command is conditional