Fix for Python 2.3 compatibility.
Note: Name of comparing function of sort() is "cmpfunc" in Python 2.3
and "cmp" in Python 2.4.
adding dir/bar
adding foo
dir/bar
foo
adding dir/bar_2
adding foo_2
dir/bar_2
foo_2
adding a
adding c
adding b
adding d
removing a
removing c
recording removal of a as rename to b (100% similar)