remove test (does not exist anymore) from flake8 command in travis
remove test (does not exist anymore) from flake8 command in travis

poldracklab/preprocessing-workflow,oesteban/fmriprep,oesteban/fmriprep,poldracklab/fmriprep,poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,oesteban/preprocessing-workflow,poldracklab/fmriprep,poldracklab/fmriprep,oesteban/fmriprep