[maven-release-plugin] prepare branch 0.6

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1437886 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare release 0.6

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1437888 13f79535-47bb-0310-9956-ffa450edef68