sct_process_segmentation: remove dead code
sct_process_segmentation: remove dead code


Former-commit-id: 3ea2d04b0ffbed85f431be0c816263c2e86f5282
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox