Set an invalid config dir in app mode to prevent accidental pickup

We don't want web apps to accidentally use configuration files from
the default folder, eg. for speed dial.

midori/main.c

@@ -1758,6 +1758,7 @@ main (int    argc,
                       NULL);
         g_object_unref (settings);
         g_object_set (browser, "settings", settings, NULL);
+        sokoke_set_config_dir ("/");
         g_signal_connect (browser, "notify::load-status",
             G_CALLBACK (midori_web_app_browser_notify_load_status_cb), NULL);
         midori_browser_add_uri (browser, webapp);