roll back to docker 1.9.1 (see comments), cache layers
roll back to docker 1.9.1 (see comments), cache layers

https://github.com/moby/moby/issues/20380

oesteban/mriqc,poldracklab/mriqc,poldracklab/mriqc,poldracklab/mriqc,oesteban/mriqc,oesteban/mriqc,oesteban/mriqc,poldracklab/mriqc