SOLR-6378: Fixed example/example-DIH/ issues with "tika" and "solr" configurations, and tidied up README.txt (merged from trunk r1618878)


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1618879 13f79535-47bb-0310-9956-ffa450edef68