This ensures the fs root is clean and does not mess with
the metadata. Also in the future this will allow for multiple
filesystems to be created in one bucket.
This also adds some generic handling of stale umounts.
Fuse returns immediately and does not indicate that
the mounter has finished writing to the backend.
The process finding is sort of hacky as I could not
find a better way to get to the PID from a fuse mount.
