les: generate random nums directly, not via strange conversions

les/retrieve.go

@@ -18,8 +18,6 @@ package les
 
 import (
 	"context"
-	"crypto/rand"
-	"encoding/binary"
 	"fmt"
 	"sync"
 	"time"
@@ -430,10 +428,3 @@ func (r *sentReq) stop(err error) {
 func (r *sentReq) getError() error {
 	return r.err
 }
-
-// genReqID generates a new random request ID
-func genReqID() uint64 {
-	var rnd [8]byte
-	rand.Read(rnd[:])
-	return binary.BigEndian.Uint64(rnd[:])
-}