Move to org.apache.catalina.ha.session.ClusterManagerBase common logics of org.apache.catalina.ha.session.BackupManager and org.apache.catalina.ha.session.DeltaManager.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1584274 13f79535-47bb-0310-9956-ffa450edef68
Revert changes from r1581820 as it triggers an IOE

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1584276 13f79535-47bb-0310-9956-ffa450edef68