[gxml] Declare GXml.Namespace implemention for old GXml.NamespaceAttr

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 16f3d5d6c2b742cd3cc4a24f205b5f238dd674f7
Author: Daniel Espinosa <esodan gmail com>
Date:   Tue Apr 14 15:00:37 2015 -0500

    Declare GXml.Namespace implemention for old GXml.NamespaceAttr

 gxml/libxml-NamespaceAttr.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gxml/libxml-NamespaceAttr.vala b/gxml/libxml-NamespaceAttr.vala
index 7a96e2c..f3578e7 100644
--- a/gxml/libxml-NamespaceAttr.vala
+++ b/gxml/libxml-NamespaceAttr.vala
@@ -30,7 +30,7 @@ namespace GXml {
         * prefix=uri pairs that define namespaces for XML Elements
         * and Attrs.
         */
-       public class NamespaceAttr : xNode {
+       public class NamespaceAttr : xNode, GXml.Namespace {
                /** Private properties */
                private Xml.Ns *ns; // XPATH:TODO: do they extend us?