Make header guards comply with Rule 3.2

refs: #3984

Change-Id: Iec7a0d9ff49cf6124af9e554432ee5f09a199651
diff --git a/nsync/sync-interest-container.h b/nsync/sync-interest-container.h
index 96086fa..d0b88c8 100644
--- a/nsync/sync-interest-container.h
+++ b/nsync/sync-interest-container.h
@@ -20,8 +20,8 @@
  *         Alexander Afanasyev <alexander.afanasyev@ucla.edu>
  */
 
-#ifndef SYNC_INTEREST_CONTAINER_H
-#define SYNC_INTEREST_CONTAINER_H
+#ifndef NLSR_NSYNC_SYNC_INTEREST_CONTAINER_H
+#define NLSR_NSYNC_SYNC_INTEREST_CONTAINER_H
 
 #include <ndn-cxx/util/time.hpp>
 
@@ -96,4 +96,4 @@
 
 } // Sync
 
-#endif // SYNC_INTEREST_CONTAINER_H
+#endif // NLSR_NSYNC_SYNC_INTEREST_CONTAINER_H