ISPN-4565 ReplTotalOrderVersionedStateTransferTest.testStateTransfer ran...

...dom failures

* fix NPE:CommitCommand should not trigger the PrepareCommand.
* fix timeout: CacheTopologyControlCommand should be processed in the deliver thread

https://issues.jboss.org/browse/ISPN-4565
there are many situations in which you need to use that guard, but this one is one of those nice cases in which it makes no difference: you're not invoking methods to do the trace nor creating new strings.