prevent output of fragment tags when serializing XHTML.

* xmlsave.c: prevent output of fragment tags when serializing XHTML.
diff --git a/xmlsave.c b/xmlsave.c
index ca1d876..98d5dbe 100644
--- a/xmlsave.c
+++ b/xmlsave.c
@@ -1111,6 +1111,10 @@
         xmlDtdDumpOutput(ctxt, (xmlDtdPtr) cur);
 	return;
     }
+    if (cur->type == XML_DOCUMENT_FRAG_NODE) {
+        xhtmlNodeListDumpOutput(ctxt, cur->children);
+	return;
+    }
     buf = ctxt->buf;
     if (cur->type == XML_ELEMENT_DECL) {
         xmlDumpElementDecl(buf->buffer, (xmlElementPtr) cur);