p2p/discover: drop a superfluous warning

p2p/discover/database.go

@@ -144,7 +144,7 @@ func (db *nodeDB) storeInt64(key []byte, n int64) error {
 func (db *nodeDB) node(id NodeID) *Node {
 	blob, err := db.lvl.Get(makeKey(id, nodeDBDiscoverRoot), nil)
 	if err != nil {
-		glog.V(logger.Warn).Infof("failed to retrieve node: %v", err)
+		glog.V(logger.Detail).Infof("failed to retrieve node %v: %v", id, err)
 		return nil
 	}
 	node := new(Node)