This should be done so that any attributes for ignoring certain files
when exporting can be appended to the file during the extraction step,
but ignored in the actual import. Necessary for importing the gitsetup
repository.
The `git ls-files | xargs rm` removes only files; directories which are
empty are left laying around. This later chokes the `mv` which puts the
"reduced" directory into place. Remove the empty directories as well.
Ben Boeckel
Brad King