bug#16407: Info-directory-list should always put this Emacs's info direc first

[Glenn Morris <rgm@gnu.org>]

Package: emacs
Version: 24.3
Severity: minor

The initialization of Info-directory-list is rather complicated.
Part of it uses this logic:

   Therefore, the directory of Info files that come with Emacs normally
   should come last (so that local files override standard ones), unless
   Emacs is installed into a non-standard directory. In the latter case,
   the directory of Info files that come with Emacs should be first in
   this list.

I don't think this logic makes sense any more. I think the directory of
Info files that come with Emacs should *always* be placed at the front of
the result (even before INFOPATH entries).

I assume the current logic dates from a time when it was thought likely
that a site might want to customize the Emacs info pages. I don't think
this happens any more. What I think does happen is people having
multiple versions of Emacs installed. In this case, I think Emacs
version N should always display the info pages associated with version N.
So Emacs should always put its own info directory first.