[grilo] net: avoid request_async() crash on cancellable unref

[Marc-Andre Lureau <malureau src gnome org>]

commit e823b8fe63846a9c60ebd59a8bf07e9c602a8528
Author: Marc-André Lureau <marcandre lureau gmail com>
Date:   Sat Nov 15 19:35:10 2014 +0100

    net: avoid request_async() crash on cancellable unref
    
    The caller may unref the cancellable, keep a reference on cancellable to
    avoid potential crash.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=740186

 libs/net/grl-net-wc.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/libs/net/grl-net-wc.c b/libs/net/grl-net-wc.c
index ba3f713..b020f17 100644
--- a/libs/net/grl-net-wc.c
+++ b/libs/net/grl-net-wc.c
@@ -443,6 +443,7 @@ request_clos_destroy (gpointer data)
   struct request_clos *c = (struct request_clos *) data;
 
   g_free (c->url);
+  g_clear_object (&c->cancellable);
   g_clear_pointer (&c->headers, g_hash_table_unref);
   g_free (c);
 }
@@ -772,7 +773,7 @@ get_url (GrlNetWc *self,
   c->url = g_strdup (url);
   c->headers = headers? g_hash_table_ref (headers): NULL;
   c->result = result;
-  c->cancellable = cancellable;
+  c->cancellable = g_object_ref (cancellable);
 
   g_get_current_time (&now);