data+interest: Fixing operator<<

Data packet was missing declaration of operator<< in header file.
Interest class has incorrect output of InterestLifetime parameter
(should be just number of milliseconds, without word "milliseconds"
present).

Change-Id: If2249ed033ab4b47640dfa4ea08253fdb84373d6
Refs: #1681
diff --git a/tests/unit-tests/test-interest.cpp b/tests/unit-tests/test-interest.cpp
index f02a8a8..0b397cf 100644
--- a/tests/unit-tests/test-interest.cpp
+++ b/tests/unit-tests/test-interest.cpp
@@ -341,6 +341,16 @@
 
   BOOST_CHECK_EQUAL_COLLECTIONS(Interest2, Interest2 + sizeof(Interest2),
                                 wire.begin(), wire.end());
+
+  std::ostringstream strStream;
+  BOOST_CHECK_NO_THROW(strStream << i);
+
+  BOOST_CHECK_EQUAL(strStream.str(),
+                    "/local/ndn/prefix?"
+                    "ndn.MinSuffixComponents=1&ndn.MaxSuffixComponents=1&"
+                    "ndn.ChildSelector=1&ndn.Scope=1&"
+                    "ndn.InterestLifetime=1000&"
+                    "ndn.Nonce=2&ndn.Exclude=alex,xxxx,*,yyyy");
 }
 
 BOOST_AUTO_TEST_CASE(EncodeWithLocalHeader)