[glib-networking] Avoid g_source_set_dummy_callback()

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 807504150957377647bfd340817013cb0f8fe6f4
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sat Jan 11 18:32:49 2020 -0600

    Avoid g_source_set_dummy_callback()
    
    Somehow this one usage got missed. We avoid it because Collabora
    discovered it shows up in profiling.`

 tls/base/gtlsconnection-base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tls/base/gtlsconnection-base.c b/tls/base/gtlsconnection-base.c
index 10658ad..6579777 100644
--- a/tls/base/gtlsconnection-base.c
+++ b/tls/base/gtlsconnection-base.c
@@ -1138,7 +1138,7 @@ g_tls_connection_base_create_source (GTlsConnectionBase  *tls,
   if (cancellable)
     {
       cancellable_source = g_cancellable_source_new (cancellable);
-      g_source_set_dummy_callback (cancellable_source);
+      g_source_set_callback (cancellable_source, dummy_callback, NULL, NULL);
       g_source_add_child_source (source, cancellable_source);
       g_source_unref (cancellable_source);
     }