SOLR-5464: Add option to ConcurrentSolrServer to stream pure delete requests.
SOLR-5465: SolrCmdDistributor retry logic has a concurrency race bug.
SOLR-5452: Do not attempt to proxy internal update requests.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1543301 13f79535-47bb-0310-9956-ffa450edef68