[gnome-ostree] jsondb: Ensure we return null if we have nothing to return

[Colin Walters <walters src gnome org>]

commit 59c151112d2aba602e0d4e979b007d6466f5de65
Author: Colin Walters <walters verbum org>
Date:   Thu Dec 6 19:32:51 2012 -0500

    jsondb: Ensure we return null if we have nothing to return
    
    Fixes an exception.

 src/ostbuild/js/jsondb.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/ostbuild/js/jsondb.js b/src/ostbuild/js/jsondb.js
index 7628c5a..4bdc386 100644
--- a/src/ostbuild/js/jsondb.js
+++ b/src/ostbuild/js/jsondb.js
@@ -74,7 +74,7 @@ const JsonDB = new Lang.Class({
 	    }
             prev = fname;
 	}
-        if (found)
+        if (found && prev)
             return this._path.get_child(prev);
         return null;
     },