ISPN-2714 - org.infinispan.distexec.mapreduce.TopologyAwareTwoNodesMapReduceTest.testInvokeMapperCancellation test fails randomly
ISPN-2581 StateTransferManagerImpl.waitForInitialStateTransferToComplete() returns too soon

Don't flag the initial state transfer as complete as soon as we send the
rebalance confirmation to the coordinator. It will be flagged while
processing the next topology update.