[gnome-session] util: fix bug leading to cleared child environment

[Ray Strode <halfline src gnome org>]

commit f44db069fb495e903aea0147d557ee3f0a40e011
Author: Ray Strode <rstrode redhat com>
Date:   Mon Mar 7 17:20:49 2016 -0500

    util: fix bug leading to cleared child environment
    
    The code was trying to initialize the environment with g_listenv
    the first time it was run, but instead, ended up using a cleared
    environment everytime.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754941

 gnome-session/gsm-util.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gnome-session/gsm-util.c b/gnome-session/gsm-util.c
index 5fa2130..e30cf91 100644
--- a/gnome-session/gsm-util.c
+++ b/gnome-session/gsm-util.c
@@ -498,7 +498,7 @@ gsm_util_setenv (const char *variable,
 {
         GError *bus_error;
 
-        if (child_environment)
+        if (child_environment == NULL)
                 child_environment = g_listenv ();
 
         if (!value)