SOLR-6228: Make sure that versions are checked after index and config replication is complete

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1608601 13f79535-47bb-0310-9956-ffa450edef68
Added a null check

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1608615 13f79535-47bb-0310-9956-ffa450edef68