CcnxConsumerCbr now is really CBR (no randomization).

Several corrections in blackhole-sprint scenario.
diff --git a/apps/ccnx-consumer-cbr.cc b/apps/ccnx-consumer-cbr.cc
index 5a2a759..b001ba7 100644
--- a/apps/ccnx-consumer-cbr.cc
+++ b/apps/ccnx-consumer-cbr.cc
@@ -97,12 +97,13 @@
 void
 CcnxConsumerCbr::ScheduleNextPacket ()
 {
-  // double mean = 8.0 * m_payloadSize / m_desiredRate.GetBitRate ();
+  double mean = 8.0 * m_payloadSize / m_desiredRate.GetBitRate ();
+  // std::cout << "next: " << Simulator::Now().ToDouble(Time::S) + mean << "s\n";
 
   if (!m_sendEvent.IsRunning ())
     m_sendEvent = Simulator::Schedule (
-                                       Seconds(m_randExp.GetValue ()),
-                                       // Seconds(mean),
+                                       // Seconds(m_randExp.GetValue ()),
+                                       Seconds(mean),
                                        &CcnxConsumer::SendPacket, this);
 }