[folks] telepathy: Fix nullability of a function parameter

[Philip Withnall <pwithnall src gnome org>]

commit e758f59168262cb1fea3b539c3676fdf0bbbddf6
Author: Philip Withnall <philip tecnocode co uk>
Date:   Wed Jan 8 18:45:13 2014 +0000

    telepathy: Fix nullability of a function parameter
    
    GBusNameVanishedCallbacks can legitimately have a NULL GDBusConnection
    pointer passed to them. If the formal parameter isn’t marked as
    nullable, Vala inserts an assertion which then fails and crashes.

 backends/telepathy/lib/tpf-logger.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/backends/telepathy/lib/tpf-logger.vala b/backends/telepathy/lib/tpf-logger.vala
index 8caf065..2be81ae 100644
--- a/backends/telepathy/lib/tpf-logger.vala
+++ b/backends/telepathy/lib/tpf-logger.vala
@@ -143,7 +143,7 @@ internal class Logger : GLib.Object
         });
     }
 
-  private void _logger_vanished (DBusConnection conn, string name)
+  private void _logger_vanished (DBusConnection? conn, string name)
     {
       /* The logger has vanished on the bus, so it and we are no longer valid */
       Logger._logger = null;