merge from 5.1 to 5.5

sql/log_event.h

@@ -2568,7 +2568,7 @@ class User_var_log_event: public Log_event
   User_var_log_event(THD* thd_arg, char *name_arg, uint name_len_arg,
                      char *val_arg, ulong val_len_arg, Item_result type_arg,
 		     uint charset_number_arg, uchar flags_arg)
-    :Log_event(), name(name_arg), name_len(name_len_arg), val(val_arg),
+    :Log_event(thd_arg,0,0), name(name_arg), name_len(name_len_arg), val(val_arg),
     val_len(val_len_arg), type(type_arg), charset_number(charset_number_arg),
     flags(flags_arg), deferred(false)
     { is_null= !val; }