Make header guards comply with Rule 3.2

refs: #3984

Change-Id: Iec7a0d9ff49cf6124af9e554432ee5f09a199651
diff --git a/nsync/sync-seq-no.h b/nsync/sync-seq-no.h
index 81955e2..b6de991 100644
--- a/nsync/sync-seq-no.h
+++ b/nsync/sync-seq-no.h
@@ -21,8 +21,8 @@
  *         Yingdi Yu <yingdi@cs.ucla.edu>
  */
 
-#ifndef SYNC_SEQ_NO_H
-#define SYNC_SEQ_NO_H
+#ifndef NLSR_NSYNC_SYNC_SEQ_NO_H
+#define NLSR_NSYNC_SYNC_SEQ_NO_H
 
 #include <boost/cstdint.hpp>
 #include "sync-digest.h"
@@ -195,4 +195,4 @@
 
 } // Sync
 
-#endif // SYNC_SEQ_NO_H
+#endif // NLSR_NSYNC_SYNC_SEQ_NO_H