applied patch from Dodji Seketeli fixing an uninitailized variable in

* valid.c: applied patch from Dodji Seketeli fixing an
  uninitailized variable in xmlValidGetValidElements()
Daniel
diff --git a/valid.c b/valid.c
index bb0bf8b..f285c19 100644
--- a/valid.c
+++ b/valid.c
@@ -5221,9 +5221,7 @@
     
     xmlElement *element_desc;
 
-    vctxt.userData = NULL;
-    vctxt.error = NULL;
-    vctxt.warning = NULL;
+    memset(&vctxt, 0, sizeof (xmlValidCtxt));
 
     if (prev == NULL && next == NULL)
         return(-1);