Cleaned up dataimport.properties errors in DIH. I did not try to prevent access denied exceptions, they still happen internally in some of the tests. I just fixed those that actually relied on persisting dataimport.properties.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene5650@1596178 13f79535-47bb-0310-9956-ffa450edef68