SOLR-6549: add a -s option to set the -Dsolr.solr.home property, thus allowing multiple Solr nodes on the same host to share the same server directory -d but with different Solr home directories

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1630550 13f79535-47bb-0310-9956-ffa450edef68