Don't generate git patches that rename a file to multiple destinations
With this patch, instead of generating N renames, we'll generate
1 rename and N-1 copies.
Ideally the rename should come after the copies instead of before
them, but that'd be harder to do.
adding a
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
pushing to ../a
abort: could not lock repository ../a: Permission denied