Adds ant script to migrate attachments to the newer version.
Adds ant script to migrate attachments to the newer version.

git-svn-id: e45ab6c9683322d5dc9a939def10e6c28e4ec7f2@1407372 13f79535-47bb-0310-9956-ffa450edef68

apache/incubator-wave,apache/incubator-wave,apache/incubator-wave,P2Pvalue/swellrt,wisebaldone/incubator-wave,P2Pvalue/swellrt,vega113/incubator-wave,vega113/incubator-wave,vega113/incubator-wave,Grasia/swellrt,apache/incubator-wave,P2Pvalue/swellrt,Grasia/swellrt,wisebaldone/incubator-wave,wisebaldone/incubator-wave,wisebaldone/incubator-wave,vega113/incubator-wave,P2Pvalue/swellrt,apache/incubator-wave,Grasia/swellrt,wisebaldone/incubator-wave,Grasia/swellrt