convert: remove incorrect and unused handling of removed svn directories Since it was introduced in f0c58fd4b798, tidy_dirs has been comparing the result of os.listdir with a string - which never can be true. Convert apparently works anyway and there is no test coverage of it. It also seems like it could make a bigger difference on older svn versions but is less relevant with more recent versions. Instead of trying to fix the code, we take the low risk option and remove it.