rib: Change validator configuration since ValidatorConfig can check timestamp now

Refs: #1643

Change-Id: I0a0b55fc4b817d6c554de800cd483cdeb6af56b8
diff --git a/nfd.conf.sample.in b/nfd.conf.sample.in
index ac3f617..05c11f8 100644
--- a/nfd.conf.sample.in
+++ b/nfd.conf.sample.in
@@ -233,7 +233,8 @@
   ;     filter
   ;     {
   ;       type name                          ; condition on interest name (w/o signature)
-  ;       regex ^[<localhop><localhost>]<nfd><rib>[<register><unregister>]<>{3}$
+  ;       regex ^[<localhop><localhost>]<nfd><rib>[<register><unregister>]<>$ ; prefix before
+  ;                                                                           ; timestamp
   ;     }
   ;     checker
   ;     {