make delete label in label setting work(backend now)

git-svn-id: https://svn.apache.org/repos/asf/james/hupa/trunk@1522369 13f79535-47bb-0310-9956-ffa450edef68
make add of label setting work in backend

git-svn-id: https://svn.apache.org/repos/asf/james/hupa/trunk@1522370 13f79535-47bb-0310-9956-ffa450edef68