Update LuceneHdfsDirectory.java

When using inside a webapp, there were a lot of open files in (CLOSED_WAIT state) for the index files on HDFS for every request. A lot of open files eventually chokes the host. Also, the FileSystem should not be closed as it is passed from outside and it could be used by others.
Update LuceneHdfsDirectory.java
closing the cloned HDFSIndexInput instances

Warning: Lucene never closes cloned IndexInputs, it will only do this on the original one. The original instance must take care that cloned instances throw AlreadyClosedException when the original one is closed. 

http://grepcode.com/file/repo1.maven.org/maven2/org.apache.lucene/lucene-core/4.0.0/org/apache/lucene/store/IndexInput.java#IndexInput.clone%28%29
closing the cloned HDFSIndexInput instances
closing the cloned HDFSIndexInput instances
Merge pull request #371 from ankurbarua/patch-1

Close cloned HDFSIndexInput instances