Mark exclude interest as mustBeFresh

refs: #4218, #4140

Change-Id: Ie85e11308ba8adf0280b8c13fb3d2b9e8084401f
diff --git a/src/logic.cpp b/src/logic.cpp
index 365eff8..a81b260 100644
--- a/src/logic.cpp
+++ b/src/logic.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
 /*
- * Copyright (c) 2012-2017 University of California, Los Angeles
+ * Copyright (c) 2012-2018 University of California, Los Angeles
  *
  * This file is part of ChronoSync, synchronization library for distributed realtime
  * applications for NDN.
@@ -765,6 +765,7 @@
   Exclude exclude = interest.getExclude();
   exclude.excludeOne(data.getFullName().get(-1));
   excludeInterest.setExclude(exclude);
+  excludeInterest.setMustBeFresh(true);
 
   excludeInterest.setInterestLifetime(m_syncInterestLifetime);