fix commit permission denied for home dipy folder

[gagnonanthony]

The COMMIT process was failing due to a OSError:

Traceback (most recent call last):
  File "/usr/local/bin/scil_run_commit.py", line 33, in <module>
    sys.exit(load_entry_point('scilpy', 'console_scripts', 'scil_run_commit.py')())
  File "/scilpy/scripts/scil_run_commit.py", line 408, in main
    commit.core.setup(ndirs=args.nbr_dir)
  File "commit/core.pyx", line 38, in commit.core.setup
  File "/usr/local/lib/python3.10/dist-packages/amico/core.py", line 41, in setup
    amico.lut.precompute_rotation_matrices( lmax, n )
  File "/usr/local/lib/python3.10/dist-packages/amico/lut.py", line 102, in precompute_rotation_matrices
    makedirs(dipy_home)
  File "/usr/lib/python3.10/os.py", line 225, in makedirs
    mkdir(name, mode)
OSError: [Errno 30] Read-only file system: '/home/lthorn2/.dipy'

After some digging, dipy is trying to create his home directory at ~/.dipy which is not writeable within a container.
Setting the DIPY_HOME variable to another path should be a sufficient fix.