LUCENE-5945: Nuke one more ZipFile usage

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1624790 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5945: Cleanup & javadocs

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1624791 13f79535-47bb-0310-9956-ffa450edef68