Better ivar name and don't hide an ivar with an lvar.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1620982 13f79535-47bb-0310-9956-ffa450edef68
Use this.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1620983 13f79535-47bb-0310-9956-ffa450edef68