face: rename hasBeenUsedRecently to hasRecentlyReceived

The word "used" is misleading, because the flag is set only when
packets are received, not for any other use of the transport.

Change-Id: I8a940d7887955c47cef085149629591b6e80c2a1
diff --git a/daemon/face/unicast-udp-transport.cpp b/daemon/face/unicast-udp-transport.cpp
index 2860559..4f8a8f7 100644
--- a/daemon/face/unicast-udp-transport.cpp
+++ b/daemon/face/unicast-udp-transport.cpp
@@ -103,12 +103,12 @@
 UnicastUdpTransport::scheduleClosureWhenIdle()
 {
   m_closeIfIdleEvent = scheduler::schedule(m_idleTimeout, [this] {
-    if (!hasBeenUsedRecently()) {
+    if (!hasRecentlyReceived()) {
       NFD_LOG_FACE_INFO("Closing due to inactivity");
       this->close();
     }
     else {
-      resetRecentUsage();
+      resetRecentlyReceived();
       scheduleClosureWhenIdle();
     }
   });