Update preprocess_t1.sh
Update preprocess_t1.sh

Former-commit-id: 31fc5cc9e4d11c5ca86084327eb41f52ac74f5a8 [formerly 42dc1b5f5f91a9df07488927720334afc379065d]
Former-commit-id: 28c2c232f0891ce638a16465145eb5ab3691ab96
Former-commit-id: e9d321123814b0361095ec2713d119259a82fa3e
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox