commit 4abdb7925c3bf91e0802e42bab6c90d9a3086b2e
Author: Dominique Leuenberger <dimstar@opensuse.org>
Date:   Tue Aug 16 16:15:21 2016 +0200

    Do not report errors in absence of dbus-update-activation-environment
    
    dbus-update-activation-environment was introduced with dbus 1.10.4
    gnome-session by itself does not depend on any specific version of
    dbus at all - but on dbus-glib-1 (DBUS_GLIB_REQUIRED=0.76)
    
    The latest version of dbus-glib (ver 106) requires dbus-1 1.8: it is
    thus a valid setup to run not have dbus-update-activation-environment
    on the system. Warning the user about its absence is alerting users
    for not reason.

diff --git a/gnome-session/gnome-session.in b/gnome-session/gnome-session.in
index 6b2ba18..5f4b303 100644
--- a/gnome-session/gnome-session.in
+++ b/gnome-session/gnome-session.in
@@ -12,6 +12,6 @@ if [ -n "$REGION" ]; then
   export LC_PAPER=$REGION
 fi
 
-dbus-update-activation-environment --all ||:
+dbus-update-activation-environment --all >& /dev/null ||:
 
 exec @libexecdir@/gnome-session-binary "$@"