BUG: fixed bug in landmark-based registration
BUG: fixed bug in landmark-based registration

Former-commit-id: 137ccd07d3dba00284250fd7771c6119e52860ee
Former-commit-id: abfbcd4090e0c84bf012cb3e6174a064041c8493
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox