[ndnSIM] Correct encoding of HopCount

Properly use NonNegativeInteger encoding instead of previously used
fixed-length 8-byte encoding of uint64_t

Change-Id: I87eae32f0ffb1ea029f8b5de754170f172ab0727
diff --git a/ndn-cxx/lp/fields.hpp b/ndn-cxx/lp/fields.hpp
index 527c405..d943880 100644
--- a/ndn-cxx/lp/fields.hpp
+++ b/ndn-cxx/lp/fields.hpp
@@ -116,8 +116,11 @@
 BOOST_CONCEPT_ASSERT((Field<PrefixAnnouncementField>));
 
 typedef FieldDecl<field_location_tags::Header,
-                  uint64_t,
-                  tlv::HopCountTag> HopCountTagField;
+                  uint16_t,
+                  tlv::HopCountTag,
+                  false,
+                  NonNegativeIntegerTag,
+                  NonNegativeIntegerTag> HopCountTagField;
 BOOST_CONCEPT_ASSERT((Field<HopCountTagField>));
 
 typedef FieldDecl<field_location_tags::Header,