mpi_discovery fails on systems with hostname executable from GNU Inetutils

Hello! I'm trying to launch DeepSpeed on my local machine with Arch Linux and inetutils 1.9.4 installed, but getting the following error:

Traceback (most recent call last):
  File "/home/me/projectsds/ai/venv/lib/python3.8/site-packages/deepspeed/__init__.py", line 110, in initialize
    engine = DeepSpeedEngine(args=args,
  File "/home/me/projectsds/ai/venv/lib/python3.8/site-packages/deepspeed/runtime/engine.py", line 137, in __init__
    init_distributed(dist_backend=self.dist_backend)
  File "/home/me/projectsds/ai/venv/lib/python3.8/site-packages/deepspeed/utils/distributed.py", line 42, in init_distributed
    mpi_discovery(distributed_port=distributed_port, verbose=verbose)
  File "/home/me/projectsds/ai/venv/lib/python3.8/site-packages/deepspeed/utils/distributed.py", line 67, in mpi_discovery
    result = subprocess.check_output(hostname_cmd, shell=True)
  File "/usr/lib/python3.8/subprocess.py", line 411, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.8/subprocess.py", line 512, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['hostname -I']' returned non-zero exit status 64.

It happens because hostname executable from Inetutils doesn't support the -I flag, but mpi_discovery function uses it.
https://github.com/microsoft/DeepSpeed/blob/8067efa41cd3a6fa67d1a7495ccceb27682bc7e5/deepspeed/utils/distributed.py#L66-L68
https://www.gnu.org/software/inetutils/manual/html_node/hostname-invocation.html

Start in deepspeed/utils/distributed.py at mpi_discovery, especially the hostname_cmd invocation linked in the issue. Check how hostname output is used during MPI discovery and verify the behavior on systems where GNU Inetutils does not support -I; done means discovery no longer fails in that environment.