[rygel] rygel: Prevent critical when there is no DBus

[Jens Georg <jensgeorg src gnome org>]

commit 0c87fb6466a5c1e14861c97950f3f7fa14a3845e
Author: Jens Georg <mail jensge org>
Date:   Tue Jun 14 21:14:53 2016 +0200

    rygel: Prevent critical when there is no DBus
    
    Signed-off-by: Jens Georg <mail jensge org>

 src/rygel/rygel-acl.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/rygel/rygel-acl.vala b/src/rygel/rygel-acl.vala
index 7a2c18f..6dea5ec 100644
--- a/src/rygel/rygel-acl.vala
+++ b/src/rygel/rygel-acl.vala
@@ -129,7 +129,7 @@ internal class Rygel.Acl : GLib.Object, GUPnP.Acl
         }
     }
 
-    private void on_name_vanished (DBusConnection connection, string name) {
+    private void on_name_vanished (DBusConnection? connection, string name) {
         this.provider = null;
     }