src: Subscribe to notifications using connect

refs: #2350

Change-Id: Ic4acedf78d2a0ea035a433ce2a05016a884503c6
diff --git a/src/nlsr.hpp b/src/nlsr.hpp
index ee6f032..639487f 100644
--- a/src/nlsr.hpp
+++ b/src/nlsr.hpp
@@ -89,7 +89,7 @@
     , m_faceMonitor(m_nlsrFace)
     , m_firstHelloInterval(FIRST_HELLO_INTERVAL_DEFAULT)
   {
-    m_faceMonitor.onNotification += ndn::bind(&Nlsr::onFaceEventNotification, this, _1);
+    m_faceMonitor.onNotification.connect(bind(&Nlsr::onFaceEventNotification, this, _1));
     m_faceMonitor.start();
   }