OPT: label_utils: minor change
OPT: label_utils: minor change

Former-commit-id: a3ac78cb3f1fae6ac834b2a5101f8aa78ac5f1d3
Former-commit-id: b740fff03c1a8cf423c8e608bed4a781b346bdc6
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox