bug#16292: 24.3.50; info docs now contain single straight quotes instead of `'

[Paul Eggert]

Drew Adams wrote:
> it seems that in this case it means that more and more Emacs users
> will get worse Info behavior in Emacs, as more and more builders
> move to a more recent Texinfo/makeinfo.

It's temporary, because we're in a feature freeze and don't
want to install the necessary feature until after the next release.
The next release should use Texinfo 4 to build the tarball, so
its info files should still use quotes `like this', and there
shouldn't be a regression.

After the feature freeze is over, we can install the necessary
feature and switch to the new Texinfo, which quotes ‘like this’,
so there still won't be a regression.  The new feature will let
installers choose to quote 'like this' if they like (which
*will* be a regression from your point of view), but that'll
be an option that you won't have to choose.