bump version to 0.17.2
bump version to 0.17.2

ContinuumIO/dask,blaze/dask,jakirkham/dask,jcrist/dask,ContinuumIO/dask,mrocklin/dask,dask/dask,jcrist/dask,mrocklin/dask,jakirkham/dask,blaze/dask,dask/dask