model+helper+examples: Enable configurability of NFD parameters using StackHelper

Refs: #2353, #2220
diff --git a/examples/ndn-simple-wifi.cpp b/examples/ndn-simple-wifi.cpp
index 8230e18..0afaa14 100644
--- a/examples/ndn-simple-wifi.cpp
+++ b/examples/ndn-simple-wifi.cpp
@@ -105,8 +105,7 @@
   ndn::StackHelper ndnHelper;
   // ndnHelper.AddNetDeviceFaceCreateCallback (WifiNetDevice::GetTypeId (), MakeCallback
   // (MyNetDeviceFaceCallback));
-  ndnHelper.SetContentStoreChoice(false);
-  ndnHelper.SetContentStore("ns3::ndn::cs::Lru", "MaxSize", "1000");
+  ndnHelper.SetOldContentStore("ns3::ndn::cs::Lru", "MaxSize", "1000");
   ndnHelper.SetDefaultRoutes(true);
   ndnHelper.Install(nodes);