sct_label_vertebrae: minor changes
sct_label_vertebrae: minor changes


Former-commit-id: 00cfa77781c4e24db30aae6a9d700c77b7b6030a
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox