face: reserved FaceIds and NullFace

refs #1620, #1622

Change-Id: I315ae262c7e0813a64b69d3e7d67de61b7b88c55
diff --git a/daemon/fw/forwarder.cpp b/daemon/fw/forwarder.cpp
index a57a756..d3fb541 100644
--- a/daemon/fw/forwarder.cpp
+++ b/daemon/fw/forwarder.cpp
@@ -92,6 +92,7 @@
     // CS lookup
     const Data* csMatch = m_cs.find(interest);
     if (csMatch != 0) {
+      const_cast<Data*>(csMatch)->setIncomingFaceId(FACEID_CONTENT_STORE);
       // XXX should we lookup PIT for other Interests that also match csMatch?
 
       // goto outgoing Data pipeline