contrib: fix import-checker to operate on str instead of bytes...
contrib: fix import-checker to operate on str instead of bytes
I believe this is fallout from other Python 3 cleanups, and our code
linting tools are now leaning towards operating on str and not
bytes. I don't feel strongly, so I've just restored this tool to
working on Python 3.
Differential Revision:
https://phab.mercurial-scm.org/D6453