moving validator files to new validator folder.

This folder will be used for all validator-related codes,
e.g. following ndns fetcher.

Change-Id: Ibdb5f35e80d914fa960edaeff7e12dd0942667b5
diff --git a/tools/ndns-update.cpp b/tools/ndns-update.cpp
index 5fdbf67..ff75417 100644
--- a/tools/ndns-update.cpp
+++ b/tools/ndns-update.cpp
@@ -20,7 +20,7 @@
 #include "clients/response.hpp"
 #include "clients/query.hpp"
 #include "ndns-label.hpp"
-#include "validator.hpp"
+#include "validator/validator.hpp"
 #include "ndns-enum.hpp"
 #include "ndns-tlv.hpp"
 #include "logger.hpp"