f add missing spaces

Author: TheBlueMatt

lightning/src/ln/peer_handler.rs

@@ -33,7 +33,7 @@ use routing::network_graph::NetGraphMsgHandler;
 use std::collections::{HashMap,hash_map,HashSet,LinkedList};
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicUsize, Ordering};
-use std::{cmp,error,hash,fmt,mem};
+use std::{cmp, error, hash, fmt, mem};
 use std::ops::Deref;
 
 use bitcoin::hashes::sha256::Hash as Sha256;