Please post the rest of Certbot's output before this.
That should be impossible. You posted the traceback before:
If I remember correctly, chardet has had a detect function for many years. Maybe since the very first version.
Please run this and show us the output:
which python2.7
python2.7 -c "import chardet; print chardet; print getattr(chardet, 'detect', None)"
That's a lot of work. It probably won't help. And if it did help, there would probably be a much easier way to accomplish the same result.
Edit: I need to finish reading the other ongoing thread...