[glib-networking] gnutls: fix g_tls_connection_gnutls_close_async to allow NULL cancellable

[Dan Winship <danw src gnome org>]

commit 5c2f4181e485c69e8f240f61273ddd2420ff412c
Author: Dan Winship <danw gnome org>
Date:   Thu Sep 22 08:44:16 2011 -0400

    gnutls: fix g_tls_connection_gnutls_close_async to allow NULL cancellable
    
    https://bugzilla.gnome.org/show_bug.cgi?id=659786

 tls/gnutls/gtlsconnection-gnutls.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index c698521..f8d624a 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -1264,7 +1264,7 @@ g_tls_connection_gnutls_close_async (GIOStream           *stream,
 
   acd = g_slice_new (AsyncCloseData);
   acd->simple = simple;
-  acd->cancellable = g_object_ref (cancellable);
+  acd->cancellable = cancellable ? g_object_ref (cancellable) : cancellable;
   acd->io_priority = io_priority;
 
   if (success)