p2p/nat: tweak port mapping log messages and levels

People stil get confused about the messages. This commit changes
the levels so that the only thing printed at the default level (info)
is a successful mapping.

p2p/nat/nat.go

@@ -86,13 +86,13 @@ func Map(m Interface, c chan struct{}, protocol string, extport, intport int, na
 	refresh := time.NewTimer(mapUpdateInterval)
 	defer func() {
 		refresh.Stop()
-		glog.V(logger.Debug).Infof("Deleting port mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
+		glog.V(logger.Debug).Infof("deleting port mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
 		m.DeleteMapping(protocol, extport, intport)
 	}()
-	glog.V(logger.Debug).Infof("add mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
 	if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil {
-		glog.V(logger.Warn).Infof("network port %d could not be mapped: %v\n", intport, err)
-		glog.V(logger.Debug).Infof("mapping with %v returned %v\n", m, err)
+		glog.V(logger.Debug).Infof("network port %s:%d could not be mapped: %v\n", protocol, intport, err)
+	} else {
+		glog.V(logger.Info).Infof("mapped network port %s:%d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
 	}
 	for {
 		select {
@@ -101,10 +101,9 @@ func Map(m Interface, c chan struct{}, protocol string, extport, intport int, na
 				return
 			}
 		case <-refresh.C:
-			glog.V(logger.Detail).Infof("refresh mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
+			glog.V(logger.Detail).Infof("refresh port mapping %s:%d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
 			if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil {
-				glog.V(logger.Warn).Infof("network port %d could not be mapped: %v\n", intport, err)
-				glog.V(logger.Debug).Infof("mapping with %v returned %v\n", m, err)
+				glog.V(logger.Debug).Infof("network port %s:%d could not be mapped: %v\n", protocol, intport, err)
 			}
 			refresh.Reset(mapUpdateInterval)
 		}