[dconf] engine: fix dconf_engine_list() with empty db

[Ryan Lortie <ryanl src gnome org>]

commit 0c9bee1cc0963f6c57dc8f7ffe9e86f216f6ac13
Author: Ryan Lortie <desrt desrt ca>
Date:   Sun Jul 15 19:53:32 2012 -0400

    engine: fix dconf_engine_list() with empty db
    
    If we opened an empty database file (like on first login) and did a
    'dconf list' on it then we would crash (due to accessing the GVDB
    without checking for NULL).
    
    Add a check.

 engine/dconf-engine.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/engine/dconf-engine.c b/engine/dconf-engine.c
index b1c0dd3..89a0c67 100644
--- a/engine/dconf-engine.c
+++ b/engine/dconf-engine.c
@@ -583,6 +583,9 @@ dconf_engine_list (DConfEngine *engine,
       gchar **partial_list;
       gint j;
 
+      if (engine->sources[i]->values == NULL)
+        continue;
+
       partial_list = gvdb_table_list (engine->sources[i]->values, dir);
 
       if (partial_list != NULL)