Set co tiled=yes to actually use blockxsize

I don't know if this is the place to fix it. If tiff is the rasterio format of choice maybe this should be fixed in `_io.pyx` instead.

The output tiff file is not actually tiled unless tiled=yes is specified. If tiled=yes is not specified GDAL silently ignores blockxsize and structures the tiff in strips.

BTW A side effect of this patch is that the IOErrors seem to disappear.