model: Fixing bug with wire format handling

When decoding Data/Interest packets, wire format was set and then
immediately (indirectly) reset to 0, leading to incorrect tracing
results (and, most likely, unnecessary performance regression).

Thanks to Tun Tun Oo for reporting the bug!
diff --git a/model/wire/ccnb/wire-ccnb-data.cc b/model/wire/ccnb/wire-ccnb-data.cc
index 0cb0b81..3b18717 100644
--- a/model/wire/ccnb/wire-ccnb-data.cc
+++ b/model/wire/ccnb/wire-ccnb-data.cc
@@ -165,13 +165,14 @@
   static DataTrailer trailer;
 
   Ptr<ndn::Data> data = Create<ndn::Data> ();
-  data->SetWire (packet->Copy ());
+  Ptr<Packet> wire = packet->Copy ();
 
   Data wireEncoding (data);
   packet->RemoveHeader (wireEncoding);
   packet->RemoveTrailer (trailer);
 
   data->SetPayload (packet);
+  data->SetWire (wire);
 
   return data;
 }