ISPN-2715 - org.infinispan.distexec.mapreduce.TopologyAwareTwoNodesMapReduceTest.testCombinerDoesNotChangeResult test fails randomly
ISPN-2581 Create unit test for state transfer completion

* Proove that config option StateTransferConfiguration.awaitInitialTransfer()
is honored correctly.
* Removed dead code.
* Log exceptions encountered during command execution as errors