pass error message from hadoop to user

[bjuergens]

current:

Traceback (most recent call last):
  File "/gpfs/smartdata/ugfam/dev/dirhash/dirhash.py", line 620, in <module>
    _main(sys.argv)
  File "/gpfs/smartdata/ugfam/dev/dirhash/dirhash.py", line 609, in _main
    h = hash_directory(args.dir, args.hash_algo, args.blocksize)
  File "/gpfs/smartdata/ugfam/dev/dirhash/dirhash.py", line 455, in hash_directory
    raw_hash = hash_directory_raw(dir, algo, _parse_blocksize(blocksize), sparkcontext)
  File "/gpfs/smartdata/ugfam/dev/dirhash/dirhash.py", line 327, in hash_directory_raw
    return hash_directory_raw(dir, algo, blocksize, sc)
  File "/gpfs/smartdata/ugfam/dev/dirhash/dirhash.py", line 339, in hash_directory_raw
    stderr=subprocess.PIPE
  File "/usr/lib64/python2.7/subprocess.py", line 575, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['hadoop', 'fs', '-ls', '-R', '/gpfs/smartdata/ugfam/dev/test_data']' returned non-zero exit status 1

when you run the internal command manually, you get a much better message:

hadoop fs -ls -R /gpfs/smartdata/ugfam/dev/test_data
ls: `/gpfs/smartdata/ugfam/dev/test_data': No such file or directory

This internal message should be passed to the user