org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.manager is now final and the unused setter API has been removed.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1596998 13f79535-47bb-0310-9956-ffa450edef68
Removed unused ivar.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1596999 13f79535-47bb-0310-9956-ffa450edef68