Method to clean solr logs for review downloads

Removes IP and DNS, replaces tokens with dummy value
Copy StatisticsClient.java to modules

source: dryad-repo/dspace-stats/src/main/java/org/dspace/statistics/util/StatisticsClient.java
commit 7f541f6921cc94aba03af968ddad878c0c82a9c0
Author: Mark Diggory <mdiggory@atmire.com>
Date:   Fri Nov 12 05:34:07 2010 +0000
Add deleteReviewIdentifiers to StatisticsClient
Remove call to optimizeSOLR() since it does not exist in SolrLogger

It exists in the original DSpace class, but the version we customized for Dryad has never had it.
Fix duplicated solr documents

Documents must be deleted and re-added with updated fields