[gnome-control-center] printers: Remove unused variable

[Marek Kašík <mkasik src gnome org>]

commit e436cf1f60f2fbf675cbb94395d3bf0ad42f15d5
Author: Robert Ancell <robert ancell canonical com>
Date:   Fri Nov 23 10:55:57 2018 +1300

    printers: Remove unused variable

 panels/printers/pp-host.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/panels/printers/pp-host.c b/panels/printers/pp-host.c
index ea5e0d16d..cbf4d0768 100644
--- a/panels/printers/pp-host.c
+++ b/panels/printers/pp-host.c
@@ -255,7 +255,6 @@ _pp_host_get_snmp_devices_thread (GTask        *task,
   g_autoptr(GError) error = NULL;
   gchar           **argv;
   gchar            *stdout_string = NULL;
-  gchar            *stderr_string = NULL;
   gint              exit_status;
 
   devices = g_new0 (PpDevicesList, 1);
@@ -268,11 +267,11 @@ _pp_host_get_snmp_devices_thread (GTask        *task,
   g_spawn_sync (NULL,
                 argv,
                 NULL,
-                0,
+                G_SPAWN_STDERR_TO_DEV_NULL,
                 NULL,
                 NULL,
                 &stdout_string,
-                &stderr_string,
+                NULL,
                 &exit_status,
                 &error);