build: Update for the new time structs in ndn-cpp-dev

Change-Id: I1dcf4bcc5ae74a37014652b8dc4b9b69fb2c670d
refs: #1373
diff --git a/ndn-traffic-server.cpp b/ndn-traffic-server.cpp
index 0e64a39..5efcb0a 100644
--- a/ndn-traffic-server.cpp
+++ b/ndn-traffic-server.cpp
@@ -342,7 +342,7 @@
     if (trafficPattern_[patternId].contentType >= 0)
       data.setContentType(trafficPattern_[patternId].contentType);
     if (trafficPattern_[patternId].freshnessPeriod >= 0)
-      data.setFreshnessPeriod(trafficPattern_[patternId].freshnessPeriod);
+      data.setFreshnessPeriod(time::milliseconds(trafficPattern_[patternId].freshnessPeriod));
     if (trafficPattern_[patternId].contentBytes >= 0)
       content = getRandomByteString(trafficPattern_[patternId].contentBytes);
     if (trafficPattern_[patternId].content != "")