make s3 test robust to extra data
make s3 test robust to extra data

amosonn/distributed,amosonn/distributed,blaze/distributed,dask/distributed,mrocklin/distributed,dask/distributed,mrocklin/distributed,amosonn/distributed,dask/distributed,broxtronix/distributed,mrocklin/distributed,dask/distributed,broxtronix/distributed,broxtronix/distributed,blaze/distributed