[gnome-control-center] network: Fix D-Bus GVariant leak

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a0c758c46b834090fa7ed536986b50ace53b966e
Author: Robert Ancell <robert ancell canonical com>
Date:   Thu Sep 12 11:53:57 2019 +1200

    network: Fix D-Bus GVariant leak

 panels/network/net-device-wifi.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/panels/network/net-device-wifi.c b/panels/network/net-device-wifi.c
index d82d43c6d..68065ab5a 100644
--- a/panels/network/net-device-wifi.c
+++ b/panels/network/net-device-wifi.c
@@ -811,6 +811,7 @@ get_hostname (void)
         if (res != NULL) {
                 g_variant_get (res, "(v)", &inner);
                 str = g_variant_dup_string (inner, NULL);
+                g_variant_unref (inner);
                 g_variant_unref (res);
         }