fix bug #316034, where xmlElemDump() can crash if given a document pointer

* xmlsave.c: fix bug #316034, where xmlElemDump() can crash if
  given a document pointer instead of an element
Daniel
diff --git a/xmlsave.c b/xmlsave.c
index 571427d..75f76a0 100644
--- a/xmlsave.c
+++ b/xmlsave.c
@@ -1086,6 +1086,11 @@
     xmlOutputBufferPtr buf;
 
     if (cur == NULL) return;
+    if ((cur->type == XML_DOCUMENT_NODE) ||
+        (cur->type == XML_HTML_DOCUMENT_NODE)) {
+        xmlDocContentDumpOutput(ctxt, (xmlDocPtr) cur);
+	return;
+    }
     if (cur->type == XML_XINCLUDE_START)
 	return;
     if (cur->type == XML_XINCLUDE_END)