SOLR-4816: Don't create "loads" of LBHttpSolrServer's, shutdown LBHttpSolrServer when appropriate, get collection from nonRoutableParams.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_5@1522690 13f79535-47bb-0310-9956-ffa450edef68