Document new attribute

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1545471 13f79535-47bb-0310-9956-ffa450edef68
Correct typo in a message

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1545480 13f79535-47bb-0310-9956-ffa450edef68