SOLR-6069: The 'clusterstatus' API should return 'roles' information

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1606035 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6044: The 'clusterstatus' API should return live_nodes as well

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1606047 13f79535-47bb-0310-9956-ffa450edef68