BUG: fixed an error on the initialization of the Ernst angle object
BUG: fixed an error on the initialization of the Ernst angle object

Former-commit-id: 76bf8b62af9aa21a9de1000e71518a2bd9f88730
Former-commit-id: 817522b3a4e82aeeaf1e149b338f1caff092c820
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox