removed @Override to compile on java 6 (for the umpteenth time...)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595414 13f79535-47bb-0310-9956-ffa450edef68
Deprecated the recently added method #getContextMap(String). Can this be removed? There are no callers...

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1595417 13f79535-47bb-0310-9956-ffa450edef68