examples: ndn-simple-with-pcap example now used CCNb packet format

The output of the example can be parsed using, for example, ndndump tool
(https://github.com/named-data/ndndump):

   ndndump -o -o ndn-simple-trace.pcap

Refs #1008 (http://redmine.named-data.net/)
diff --git a/examples/ndn-simple-with-pcap.cc b/examples/ndn-simple-with-pcap.cc
index 6499db7..fb01947 100644
--- a/examples/ndn-simple-with-pcap.cc
+++ b/examples/ndn-simple-with-pcap.cc
@@ -56,6 +56,8 @@
   Config::SetDefault ("ns3::PointToPointChannel::Delay", StringValue ("10ms"));
   Config::SetDefault ("ns3::DropTailQueue::MaxPackets", StringValue ("20"));
 
+  Config::SetDefault ("ns3::ndn::Face::WireFormat", StringValue ("1"));
+
   // Creating nodes
   NodeContainer nodes;
   nodes.Create (3);