bug#42271: 27.0.91; Variable global-auto-revert-ignore-modes not working

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Thu, 9 Jul 2020 00:18:51 +0200
> Cc: 42271@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>
> 
> Thank you! It's my mistake and I'm very sorry about it.
> 
> Eli, this is a regression introduced in Emacs 27 and the fix amounts to the 
> removal of a single quote. Can we do it on emacs-27?

Yes, of course.

Thanks.