https://issues.apache.org/jira/browse/AMQ-4328 - AMQ3274Test, org.apache.activemq.usecases.NetworkBridgeProducerFlowControlTest - sync needs to be conditional

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1448809 13f79535-47bb-0310-9956-ffa450edef68