fib: fix route unregister bug during update

refs: #5179

Change-Id: I19952ebcb0c78c405f3d820694a7b0f1cf7a3fe6
diff --git a/src/route/fib.hpp b/src/route/fib.hpp
index e8f8a40..25b5956 100644
--- a/src/route/fib.hpp
+++ b/src/route/fib.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2020,  The University of Memphis,
+ * Copyright (c) 2014-2021,  The University of Memphis,
  *                           Regents of the University of California,
  *                           Arizona Board of Regents.
  *
@@ -31,11 +31,13 @@
 
 namespace nlsr {
 
+typedef NexthopListT<NextHopUriSortedComparator> NextHopsUriSortedSet;
+
 struct FibEntry {
   ndn::Name name;
   ndn::scheduler::ScopedEventId refreshEventId;
   int32_t seqNo = 1;
-  NexthopList nexthopList;
+  NextHopsUriSortedSet nexthopSet;
 };
 
 typedef std::function<void(FibEntry&)> afterRefreshCallback;
@@ -153,7 +155,7 @@
    * \sa Fib::removeOldNextHopsFromFibEntryAndNfd
    */
   void
-  addNextHopsToFibEntryAndNfd(FibEntry& entry, const NexthopList& hopsToAdd);
+  addNextHopsToFibEntryAndNfd(FibEntry& entry, const NextHopsUriSortedSet& hopsToAdd);
 
   unsigned int
   getNumberOfFacesForName(const NexthopList& nextHopList);