Some small cleanups for convert extension:
- repo doesn't need to be imported
- util.Abort doesn't need \n
- space after comma
- long lines
- spacing
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)