OPT: register_to_template: fixed bug
OPT: register_to_template: fixed bug

Former-commit-id: cbf4554e43011a7272e5563539f70e879558d5eb
Former-commit-id: bf2d03a2f7a4ff026d8a39afdb3858922de049e0
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox