removed the preLoadLimit logic since it was causing the RoundRobingDispatchPolicyTests to fail intermitently. The preLoadLimit was an additional prefetch limit, and when it kicked in, it would cause the round robin distribution to stop sending round robin.
incubator/activemq/trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java