[maven-release-plugin] rollback the release of 0.2.1
[maven-release-plugin] rollback the release of 0.2.1

lewis-ing/aerogear-unifiedpush-java-client,yvnicolas/aerogear-unifiedpush-java-client,matzew/aerogear-unifiedpush-java-client,aerogear/aerogear-unifiedpush-java-client