fix test breakage after: https://issues.apache.org/jira/browse/AMQ-3833

The producerAudit is only written out on change so in this test it holds onto another log file meaning there are two left instead of one.

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1434074 13f79535-47bb-0310-9956-ffa450edef68