Update versions for release

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1454570 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare release org.apache.felix.main.distribution-4.2.1

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1454572 13f79535-47bb-0310-9956-ffa450edef68