REF: register_to_template: removed system call
REF: register_to_template: removed system call

Former-commit-id: 15ba15f741220099f9e5a933cff0847480834e5a
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox