HADOOP-4952 calls for a create call that doesn't automatically create missing parent directories.
Support non-recursive create() in FileSystem API
LocalFileSystem Needs createNonRecursive API
Support non-recursive create() in FileSystem & SequenceFile.Writer
Possible data loss when RS goes into GC pause while rolling HLog
Atempt to make a directory under an existing file on DistributedFileSystem should throw an FileAlreadyExistsException instead of FileNotFoundException
Improved files system interface for the application writer.