Turn off random seeding for ANTs brain extraction
Turn off random seeding for ANTs brain extraction

This would make the brain extraction results fully replicable when used with `--omp-nthreads 1`.
See https://github.com/poldracklab/fmriprep/issues/917
oesteban/fmriprep,oesteban/fmriprep,poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,poldracklab/preprocessing-workflow,oesteban/fmriprep,poldracklab/fmriprep,poldracklab/fmriprep,oesteban/preprocessing-workflow,poldracklab/fmriprep