applied fixes for a couple of potential security problems more fixes on

* nanoftp.c: applied fixes for a couple of potential security problems
* tree.c valid.c xmllint.c: more fixes on the string interning checks
Daniel
diff --git a/valid.c b/valid.c
index 2ce83b1..b853992 100644
--- a/valid.c
+++ b/valid.c
@@ -6697,8 +6697,7 @@
     /*
      * Creates a dummy node and insert it into the tree
      */    
-    test_node = xmlNewNode (NULL, BAD_CAST "<!dummy?>");
-    test_node->doc = ref_node->doc;
+    test_node = xmlNewDocNode (ref_node->doc, NULL, BAD_CAST "<!dummy?>", NULL);
     test_node->parent = parent;
     test_node->prev = prev;
     test_node->next = next;