added unsubscribeFromTheCurrentlyConsumedSerialsCollectively()
DataCenterTests.VerifyAvailabilityOfDerivedProductSubpools_Test()
was improved to fix avoid: Runtime Error No row with the given
identifier exists:
[org.candlepin.model.PoolAttribute#8a99f98a46b4fa990146ba9494032318]
at org.hibernate.UnresolvableObjectException.throwIfNull:64