Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=51294
This is an initial implementation that includes some but not all the anticipated test cases. It is expected that as the test cases are expanded, further changes will required.
Remove the comments from the context.xml files that have been replaced by using the sessionCookieName.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1482288 13f79535-47bb-0310-9956-ffa450edef68