[gxml] Ported XParser to Vala upstream

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 8198b8720d94a85d70152ccdc218442827cde829
Author: Daniel Espinosa <esodan gmail com>
Date:   Thu Oct 26 11:35:33 2017 -0500

    Ported XParser to Vala upstream

 gxml/XParser.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gxml/XParser.vala b/gxml/XParser.vala
index 71a42c4..b053020 100644
--- a/gxml/XParser.vala
+++ b/gxml/XParser.vala
@@ -682,7 +682,7 @@ public class GXml.XParser : Object, GXml.Parser {
         tw.flush ();
     }
     if (n is GXml.DomDocumentType) {
-      size += tw.write_document_type ((n as DomDocumentType).name,
+      size += tw.write_dtd ((n as DomDocumentType).name,
                           (n as DomDocumentType).public_id,
                           (n as DomDocumentType).system_id,
                           null);