Detects if a Logger with the specified name exists. This is a convenience method for porting from version 1.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1581076 13f79535-47bb-0310-9956-ffa450edef68
Fix JavaDoc variable reference.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1581077 13f79535-47bb-0310-9956-ffa450edef68