Simplify some code with Boost.Operators

Change-Id: Ic873bcbaf6be00d5c35601cfc8090df534d815ee
diff --git a/daemon/rib/fib-update.hpp b/daemon/rib/fib-update.hpp
index fd80b89..edf6c00 100644
--- a/daemon/rib/fib-update.hpp
+++ b/daemon/rib/fib-update.hpp
@@ -28,12 +28,14 @@
 
 #include "core/common.hpp"
 
+#include <boost/operators.hpp>
+
 namespace nfd::rib {
 
 /**
  * \brief Represents a FIB update.
  */
-class FibUpdate
+class FibUpdate : private boost::equality_comparable<FibUpdate>
 {
 public:
   enum Action {
@@ -57,12 +59,6 @@
            lhs.action == rhs.action;
   }
 
-  friend bool
-  operator!=(const FibUpdate& lhs, const FibUpdate& rhs) noexcept
-  {
-    return !(lhs == rhs);
-  }
-
 public:
   Name name;
   uint64_t faceId = 0;