time: Adapt to ndn-cpp-dev's new time structure

Change-Id: I4117d4e7aea5347cbaf3ec2e5e5a110f94930262
diff --git a/src/endorse-certificate.cpp b/src/endorse-certificate.cpp
index 3d1f298..3aef18e 100644
--- a/src/endorse-certificate.cpp
+++ b/src/endorse-certificate.cpp
@@ -106,8 +106,8 @@
 
 EndorseCertificate::EndorseCertificate(const Name& keyName,
                                        const PublicKey& key,
-                                       MillisecondsSince1970 notBefore,
-                                       MillisecondsSince1970 notAfter,
+                                       const time::system_clock::TimePoint& notBefore,
+                                       const time::system_clock::TimePoint& notAfter,
                                        const Name& signer,
                                        const Profile& profile,
                                        const vector<string>& endorseList)