fix case ES preindex

http://manage.dimagi.com/default.asp?147543

depends on https://github.com/dimagi/pillowtop/pull/96
see: https://github.com/dimagi/pillowtop/pull/96/files#diff-6dac4be25b780fb79c406285662331fcR769

I think if we change it then every other pillow will have to reindex since the checkpoint will change (which i would like to avoid)