BUG: label_utils: fixed bug with "remove"
BUG: label_utils: fixed bug with "remove"

Former-commit-id: e0cc9174b05d8351497fe2ab096ae90b521729f8 [formerly 8cb70f9015ff7299a12aaafe4ec8b35962181640]
Former-commit-id: 20f845c975c6569452a9b06406447ed37e6464f5
Former-commit-id: bf5b6ce9c6cca2fb8fba0f1efc9a94884d60347a
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox