CcnxConsumerCbr now is really CBR (no randomization).

Several corrections in blackhole-sprint scenario.
diff --git a/examples/blackhole-sprint.cc b/examples/blackhole-sprint.cc
index 9b8fcfc..dba634a 100644
--- a/examples/blackhole-sprint.cc
+++ b/examples/blackhole-sprint.cc
@@ -294,6 +294,7 @@
           continue;
 
         CcnxAppHelper consumerHelper ("ns3::CcnxConsumerCbr");
+        consumerHelper.SetAttribute ("LifeTime", StringValue("100s"));
         BOOST_FOREACH (const string &prefix, prefixes)
           {
             consumerHelper.SetPrefix (prefix);
@@ -317,7 +318,7 @@
   
   Config::SetDefault ("ns3::PointToPointNetDevice::DataRate", StringValue ("100Mbps"));
   Config::SetDefault ("ns3::DropTailQueue::MaxPackets", StringValue ("2000"));
-  Config::SetDefault ("ns3::RttEstimator::InitialEstimation", StringValue ("1s"));
+  Config::SetDefault ("ns3::RttEstimator::InitialEstimation", StringValue ("0.5s"));
 
   Config::SetDefault ("ns3::ConfigStore::Filename", StringValue ("attributes.xml"));
   Config::SetDefault ("ns3::ConfigStore::Mode", StringValue ("Save"));