rib: add proper #include line for ndn::OBufferStream

refs #3741

Change-Id: If08719fac9e977bd5d68c1aba491738eacbfa900
diff --git a/rib/rib-manager.hpp b/rib/rib-manager.hpp
index a27d353..7f63745 100644
--- a/rib/rib-manager.hpp
+++ b/rib/rib-manager.hpp
@@ -33,6 +33,7 @@
 #include "auto-prefix-propagator.hpp"
 #include "fib-updater.hpp"
 
+#include <ndn-cxx/encoding/buffer-stream.hpp>
 #include <ndn-cxx/security/validator-config.hpp>
 #include <ndn-cxx/management/nfd-face-monitor.hpp>
 #include <ndn-cxx/management/nfd-controller.hpp>