Fix rustc warnings

beacon_node/eth2-libp2p/src/behaviour.rs

@@ -7,7 +7,6 @@ use futures::prelude::*;
 use libp2p::{
     core::identity::Keypair,
     discv5::Discv5Event,
-    enr::Enr,
     gossipsub::{Gossipsub, GossipsubEvent},
     identify::{Identify, IdentifyEvent},
     ping::{Ping, PingConfig, PingEvent},

beacon_node/eth2-libp2p/src/service.rs

@@ -15,7 +15,7 @@ use libp2p::core::{
     transport::boxed::Boxed,
     upgrade::{InboundUpgradeExt, OutboundUpgradeExt},
 };
-use libp2p::{core, enr::Enr, secio, PeerId, Swarm, Transport};
+use libp2p::{core, secio, PeerId, Swarm, Transport};
 use slog::{debug, info, trace, warn};
 use std::fs::File;
 use std::io::prelude::*;