Re-implement `renameDirAlmostAtomically` in `Builder#complete`.
Re-implement `renameDirAlmostAtomically` in `Builder#complete`.

The `rename` is not sufficient on its own since it won't pave the way
for the new directory by ensuring that it's empty first.

`renameDirAlmostAtomically` will do that.

Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor