core: use ndn-cxx scheduler::ScopedEventId

refs #4698

Change-Id: I5ab56855fb22824e129fd7e3ccfb53174cf34f82
diff --git a/rib/route.hpp b/rib/route.hpp
index cc4ff02..05449e2 100644
--- a/rib/route.hpp
+++ b/rib/route.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2018,  Regents of the University of California,
+ * Copyright (c) 2014-2019,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -60,17 +60,15 @@
   }
 
   void
-  setExpirationEvent(const ndn::util::scheduler::EventId& eid, ndn::util::Scheduler& scheduler)
+  setExpirationEvent(const ndn::util::scheduler::EventId& eid)
   {
     m_expirationEvent = eid;
-    m_scheduler = &scheduler;
   }
 
   void
-  cancelExpirationEvent() const
+  cancelExpirationEvent()
   {
-    if (m_scheduler)
-      m_scheduler->cancelEvent(m_expirationEvent);
+    m_expirationEvent.cancel();
   }
 
   std::underlying_type<ndn::nfd::RouteFlags>::type
@@ -104,7 +102,6 @@
 
 private:
   ndn::util::scheduler::EventId m_expirationEvent;
-  ndn::util::Scheduler* m_scheduler;
 };
 
 bool