fix issue with caching bindle assets

[simongdavies]

Fix for issue where mapping bindle to wagi config mounts the wrong path as a volume.

[technosophos]

I am reverting this one because this mounts one directory level to high. So for example, this should work:

$ curl -v localhost:3000/static/README.md

But it does not. And this should not work (basically, getting a file out of a parcel by SHA):

$ curl -v localhost:3000/static/158acdedb8163ad1e25822bbe51934663aca021f8d68bd91338e8f3d578dac7c/README.md

And the above does in fact work.