NIOFSDirectory is not implemented in Lucene.Net. So returning NIOFSDirectory as default directory on mono is wrong.
NIOFSDirectory is not implemented in Lucene.Net. So returning NIOFSDirectory as default directory on mono is wrong.

git-svn-id: b2dcba4c53c5fa0a86ccceee81d7e0ce197ae049@930561 13f79535-47bb-0310-9956-ffa450edef68

zmaruo/lucenenet,apache/lucenenet,mdissel/lucene.net,apache/lucenenet,jpsullivan/lucenenet,zmaruo/lucenenet,NightOwl888/lucenenet,NightOwl888/lucenenet,jeme/lucenenet,jeme/lucenenet,laimis/lucenenet,mdissel/lucene.net,sisve/lucenenet,antiufo/lucenenet,NightOwl888/lucenenet,jeme/lucenenet,laimis/lucenenet,NightOwl888/lucenenet,jeme/lucenenet,apache/lucenenet,jpsullivan/lucenenet,sisve/lucenenet,antiufo/lucenenet,apache/lucenenet