unstaging flag returns false instead of true for completed transactions

Hi Richard Ponton:

Sometimes, the unstaging flag is returning the value as "false" instead of "true" for transactions in "completed" state

for eg: readWritePermissionsOnCollectionsOfTxnOperationAndATR[1] – com.couchbase.transactions.RbacOnCollectionsTest in below job:

http://sdk.jenkins.couchbase.com/blue/organizations/jenkins/dotnet%2Fsdk%2FTransactionsFITPerformer_SinglePerformer/detail/TransactionsFITPerformer_SinglePerformer/193/tests

We had similar issue in CXX as well:

https://issues.couchbase.com/browse/TXNCXX-130