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

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: 16407@debbugs.gnu.org
> Date: Fri, 10 Jan 2014 15:05:57 -0500
> 
> I was thinking of having several Emacs versions installed in different
> directories.

You mean, configured with a different --prefix?  Do people actually do
this when installing programs, except when they are installed for a
single user under her home directory?  Do they do this frequently
enough for us to care?