git fast-export bug when using rename detection and paths contain spaces

Repro:

git init temp-repo && cd temp-repo &&
echo foo > "foo file" && git add "foo file" && git commit -m foo &&
git mv "foo file" "bar file" && git commit -m "rename foo to bar" &&
git fast-export -C -M HEAD | grep ^R

Outputs:

  R foo file bar file

It should output:

  R "foo file" "bar file"

This was allegedly fixed by 6280dfdc3b (fast-export: quote paths in
output, 2011-08-05). It seems that that commit expects quote_c_style
to output surrounded quotes when the path contains spaces, but both
empirically and from my quick look at quote_c_style, it doesn't seem
that the function does that.

Sadly, I don't have time to submit a fix ATM.

j.