Fixes APLO-296: Support configuring the LevelDB auto compaction frequency

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-apollo/trunk@1448654 13f79535-47bb-0310-9956-ffa450edef68
Fix for APLO-297: java.lang.IllegalArgumentException in recent snapshot

Synchronize access to the hash set.

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-apollo/trunk@1448655 13f79535-47bb-0310-9956-ffa450edef68
Fixes: APLO-298 UOW warnings in latest snapshot

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-apollo/trunk@1448657 13f79535-47bb-0310-9956-ffa450edef68