[gnome-session] systemd: add better error reporting

[Ray Strode <halfline src gnome org>]

commit 4d3d4f67c6022d9f0d540a3f25f730b088288d92
Author: Ray Strode <rstrode redhat com>
Date:   Fri Mar 9 10:41:07 2012 -0500

    systemd: add better error reporting
    
    commit 079398edaa added better handling for systemd
    failing, but it used the wrong variable for reporting
    which message to give.
    
    This commit changes the code to use the right error
    variable.
    
    Spotted by Hans de Goede

 gnome-session/gsm-systemd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gnome-session/gsm-systemd.c b/gnome-session/gsm-systemd.c
index 7704271..5bf64b0 100644
--- a/gnome-session/gsm-systemd.c
+++ b/gnome-session/gsm-systemd.c
@@ -365,7 +365,7 @@ gsm_systemd_is_login_session (GsmSystem *system)
 
         res = sd_session_get_service (manager->priv->session_id, &service);
         if (res < 0) {
-                g_warning ("could not get pam service: %s", strerror (-ret));
+                g_warning ("could not get pam service: %s", strerror (-res));
                 return FALSE;
         }
         ret = (g_strcmp0 (service, "gdm-welcome") == 0);