rib: introduce ReadvertisePolicy

refs #3818

Change-Id: Id40a7dfeeb1c46d6bff0750b15f3288a10897288
diff --git a/rib/readvertise/readvertised-route.hpp b/rib/readvertise/readvertised-route.hpp
index 1a896b1..0692ccd 100644
--- a/rib/readvertise/readvertised-route.hpp
+++ b/rib/readvertise/readvertised-route.hpp
@@ -48,19 +48,13 @@
   mutable scheduler::ScopedEventId retryEvt; ///< retry or refresh event
 };
 
-/** \brief a less than comparison functor for ReadvertisedRoute prefix
- */
-class ReadvertisedRoutePrefixCompare
+inline bool
+operator<(const ReadvertisedRoute& lhs, const ReadvertisedRoute& rhs)
 {
-public:
-  bool
-  operator()(const ReadvertisedRoute& lhs, const ReadvertisedRoute& rhs)
-  {
-    return lhs.prefix < rhs.prefix;
-  }
-};
+  return lhs.prefix < rhs.prefix;
+}
 
-using ReadvertisedRouteContainer = std::set<ReadvertisedRoute, ReadvertisedRoutePrefixCompare>;
+using ReadvertisedRouteContainer = std::set<ReadvertisedRoute>;
 
 } // namespace rib
 } // namespace nfd