minor.

lib/bcoin/chain.js

@@ -1121,7 +1121,7 @@ Chain.prototype.add = function add(initial, peer, callback, force) {
 
         self.emit('fork', block, {
           height: entry.height,
-          expected: network.checkpoints[entry.height],
+          expected: checkpoint,
           received: entry.hash,
           checkpoint: true
         }, peer);