conf: Make event intervals configurable

User can specify the intervals for the first Hello Interest,
AdjLsa building, and routing calculation in the conf file.

refs: #2071

Change-Id: Ic8eb29d433069086955178bc42b5f8fc8f4149d3
diff --git a/src/route/routing-table.cpp b/src/route/routing-table.cpp
index 09b9430..371d977 100644
--- a/src/route/routing-table.cpp
+++ b/src/route/routing-table.cpp
@@ -156,7 +156,7 @@
 RoutingTable::scheduleRoutingTableCalculation(Nlsr& pnlsr)
 {
   if (pnlsr.getIsRouteCalculationScheduled() != true) {
-    m_scheduler.scheduleEvent(ndn::time::seconds(15),
+    m_scheduler.scheduleEvent(m_routingCalcInterval,
                               ndn::bind(&RoutingTable::calculate, this, ndn::ref(pnlsr)));
 
     pnlsr.setIsRouteCalculationScheduled(true);