Message 263701 - Python tracker

`shutil.get_terminal_size()` will sometimes propagate `AttributeError: module <os> has not attribute 'get_terminal_size'` to the caller. The call checks for NameError, which makes no sense, so I guess it must be an oversight. Attached patch fixes it.

(diff was generated with git, I don't know if it works with Mercurial, but it's a trivial change anyway)