py3: use pycompat.ossep at certain places
Certain instances of os.sep has been converted to pycompat.ossep where it was
sure to use bytes only. There are more such instances which needs some more
attention and will get surely.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.