SOLR-4553: Bug in finding remote node when proxying update request in a cluster with more than one collection.
Also, attempt to proxy requests more aggressively.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1545068 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5497: Do not try and start a jetty that is not stopped

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1545069 13f79535-47bb-0310-9956-ffa450edef68