Bug 1212413

I think was during steam updating. so not sure if steam does any fiddling with env vars.

```
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00005590ab93339d in zenity_util_gapp_quit (window=0x5590ad5717c0, data=<optimized out>) at ../src/util.c:465
Downloading 0.01 MB source file /usr/src/debug/zenity-3.92.0/x86_64-suse-linux/../src/util.c
465                     g_assert (GTK_IS_WINDOW (window));                                                                                                                                                                                                                                                                    
[Current thread is 1 (Thread 0x7f4498982dc0 (LWP 3231))]
(gdb) bt
#0  0x00005590ab93339d in zenity_util_gapp_quit (window=0x5590ad5717c0, data=<optimized out>) at ../src/util.c:465
#1  0x00005590ab937761 in zenity_progress_handle_stdin (channel=0x5590af938950, condition=<optimized out>, data=<optimized out>) at ../src/progress.c:294
#2  0x00007f4499d2b8d8 in g_main_dispatch (context=0x5590ad42db90) at ../glib/gmain.c:3460
#3  g_main_context_dispatch (context=context@entry=0x5590ad42db90) at ../glib/gmain.c:4200
#4  0x00007f4499d2bce8 in g_main_context_iterate (context=context@entry=0x5590ad42db90, block=block@entry=0, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4276
#5  0x00007f4499d2bd7c in g_main_context_iteration (context=context@entry=0x5590ad42db90, may_block=may_block@entry=0) at ../glib/gmain.c:4343
#6  0x00007f4499efb912 in g_application_run (application=application@entry=0x5590ad42ba20, argc=argc@entry=0, argv=argv@entry=0x0) at ../gio/gapplication.c:2604
#7  0x00005590ab932725 in main (argc=9, argv=<optimized out>) at ../src/main.c:160
```