Purge obsolete files from the staging and production sites

1. http://community.nuxeo.com/static/drive-tests/latest/ is not used anymore and should be deleted.
2. There are several xxx-SNAPSHOT.json files in http://community.nuxeo.com/static/drive-tests/ and http://community.nuxeo.com/static/drive/ that are obsoletes too.

To discuss:
3. Should we remove packages from http://community.nuxeo.com/static/drive-tests/ that are published in http://community.nuxeo.com/static/drive/ ? If one is onto the production site, then it should not belong to the beta one.