SOLR-5520: Backports of:
- SOLR-4881 (Fix DocumentAnalysisRequestHandler to correctly use EmptyEntityResolver to prevent loading of external entities like UpdateRequestHandler does)
- SOLR-3895 (XML and XSLT UpdateRequestHandler should not try to resolve external entities)
- SOLR-3614 (Fix XML parsing in XPathEntityProcessor to correctly expand named entities, but ignore external entities)


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_3_6@1547011 13f79535-47bb-0310-9956-ffa450edef68