BUG: fixed some bugs in sct_register_pipeline
BUG: fixed some bugs in sct_register_pipeline

Former-commit-id: 2116877f6dc599e55e239c0b76c4170cdda04284 [formerly 0acf20e0632ce0af6824e124a373c6e57b7c194f]
Former-commit-id: 7a3431fb7c695072dcffdb2e736636019be7f2cd
Former-commit-id: dd618af2bf1039b042ead010647583bb52825220
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox