[maven-release-plugin] prepare branch activemq-cpp-3.6.x

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-cpp/trunk@1451252 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare release activemq-cpp-3.6.x

git-svn-id: https://svn.apache.org/repos/asf/activemq/activemq-cpp/trunk@1451254 13f79535-47bb-0310-9956-ffa450edef68