SOLR-5085: the point of the subdir is so the files wouldn't have 'rc' in their name, and could be copied as is ... fix script to split X.Y-RCZ to build final file names, and vet that args look correct

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1526271 13f79535-47bb-0310-9956-ffa450edef68