BUG: Create tmp folder only once. see #685.
BUG: Create tmp folder only once. see #685.

Former-commit-id: c69402d5879c4e4c88b687cd030bdc7d9e698c38 [formerly 7b71bd0c27134e17c742efe359fcc64a543d6ead]
Former-commit-id: 58971cb933baa875c78639657e80d58c1ca63ae2
Former-commit-id: cd418051d7dbe3cabf41aa9553b574c951e3242c
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox