applications.menu file has been renamed to gnome-applications.menu but XDG_MENU_PREFIX is not set

Hello,

Firstly, thank you for maintaining all these gnome packages!

The latest version of gnome-menus has renamed applications.menu file: https://bazaar.launchpad.net/~ubuntu-branches/ubuntu/saucy/gnome-menus/saucy/revision/136/debian/gnome-menus.maintscript

    gnome-menus.maintscript:
    - Clean up after rename from /etc/xdg/menus/applications.menu
       to /etc/xdg/menus/gnome-applications.menu

But this environment variable is not set: XDG_MENU_PREFIX:

    $ test -z "$XDG_MENU_PREFIX" && echo null || echo $XDG_MENU_PREFIX
    null
    $ echo $XDG_CURRENT_DESKTOP
    GNOME
    $ echo $DESKTOP_SESSION
    cairo-dock

Here is the standards: https://developer.gnome.org/menu-spec/ => "Desktop Menu Specification"

______
 Here are the files defined by this specification:

$XDG_CONFIG_DIRS/menus/${XDG_MENU_PREFIX}applications.menu

    This file contains the XML definition of the main application menu layout. The first file found in the search path should be used; other files are ignored. This implies that if the user has their own ${XDG_MENU_PREFIX}applications.menu, it replaces the system wide one. (Though the user's menu may explicitly merge the system wide one.)

    Systems that offer multiple desktop environments and that want to use distinct menu layouts in the different environments can use differently prefixed .menu files. In this case the $XDG_MENU_PREFIX environment variable must be set by the system to reflect the .menu file that is being used.

    For example if a system contains both the GNOME and the KDE desktop environments it can decide to use gnome-applications.menu as the menu layout in GNOME sessions and kde-applications.menu as the menu layout in KDE sessions. To correctly reflect this, it should set the $XDG_MENU_PREFIX environment variable to "gnome-" respectively "kde-".

    Implementations may chose to use .menu files with other names for tasks or menus other than the main application menu. Such usage is not covered by this specification.
______

According to this document, the $XDG_MENU_PREFIX environment variable should contain "gnome-"

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: gnome-menus 3.8.0-1ubuntu3
ProcVersionSignature: Ubuntu 3.9.0-6.13-generic 3.9.6
Uname: Linux 3.9.0-6-generic x86_64
ApportVersion: 2.10.2-0ubuntu1
Architecture: amd64
Date: Sat Jun 15 15:06:24 2013
InstallationDate: Installed on 2011-08-10 (674 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110803.1)
MarkForUpload: True
SourcePackage: gnome-menus
UpgradeStatus: No upgrade log present (probably fresh install)