chunks+peek+ping: use correct underlying type for time::milliseconds

Change-Id: I3f46f846401eccc0c11d3abcd1a5ebff89056f7d
diff --git a/tools/peek/ndnpeek/ndnpeek.cpp b/tools/peek/ndnpeek/ndnpeek.cpp
index 8969216..ff7f7a0 100644
--- a/tools/peek/ndnpeek/ndnpeek.cpp
+++ b/tools/peek/ndnpeek/ndnpeek.cpp
@@ -62,12 +62,10 @@
   Interest interest(m_options.name);
   interest.setCanBePrefix(m_options.canBePrefix);
   interest.setMustBeFresh(m_options.mustBeFresh);
+  interest.setInterestLifetime(m_options.interestLifetime);
   if (m_options.link) {
     interest.setForwardingHint(m_options.link->getDelegationList());
   }
-  if (m_options.interestLifetime) {
-    interest.setInterestLifetime(*m_options.interestLifetime);
-  }
 
   if (m_options.isVerbose) {
     std::cerr << "INTEREST: " << interest << std::endl;