SOLR-4952: TestSolrDeletionPolicy2 can't directly use solrconfig.snippet.randomindexconfig.xml - but it can leverage the random sys props directly

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1511139 13f79535-47bb-0310-9956-ffa450edef68