Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=52558
Refactor CometConnectionManagerValve so that it does not prevent the session from being serialized in when running in a cluster. 

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1522526 13f79535-47bb-0310-9956-ffa450edef68