[dconf] Don't crash on DBus connection failure

[Ryan Lortie <ryanl src gnome org>]

commit 3381a536337b69a3ba54543d69624fb2274ffa66
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Jan 31 11:02:35 2011 -0500

    Don't crash on DBus connection failure
    
    When adding matches, if we can't connect to DBus, the code will
    presently crash.  This fixes that.

 gsettings/dconfsettingsbackend.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/gsettings/dconfsettingsbackend.c b/gsettings/dconfsettingsbackend.c
index abba2a1..d978646 100644
--- a/gsettings/dconfsettingsbackend.c
+++ b/gsettings/dconfsettingsbackend.c
@@ -518,6 +518,13 @@ add_match_done (GObject      *source,
   GError *error = NULL;
   GVariant *reply;
 
+  /* couldn't connect to DBus */
+  if (source == NULL)
+    {
+      outstanding_watch_free (watch);
+      return;
+    }
+
   reply = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source),
                                          result, &error);