Remove obsolete "Alternative Status Menu" from the list of enabled GNOME Shell extensions.

It's not shipped in Debian anymore (https://bugs.debian.org/782747).

Refs: #10842

config/chroot_local-includes/etc/dconf/db/local.d/00_Tails_defaults

@@ -85,5 +85,5 @@ antialiasing = 'rgba'
 hinting = 'slight'
 
 [org/gnome/shell]
-enabled-extensions = ['alternative-status-menu@gnome-shell-extensions.gcampax.github.com', 'topIcons@adel.gadllah@gmail.com', 'shutdown-helper@tails.boum.org']
+enabled-extensions = ['topIcons@adel.gadllah@gmail.com', 'shutdown-helper@tails.boum.org']
 favorite-apps=['tor-browser.desktop', 'icedove.desktop', 'pidgin.desktop', 'keepassx.desktop', 'gnome-terminal.desktop']