LUCENE-4870: Lucene deletes entire index if and exception is thrown due do TooManyOpenFiles and OpenMode.CREATE_OR_APPEND

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_2@1459909 13f79535-47bb-0310-9956-ffa450edef68