torrent.js: depend on local './swarm' file

lib/torrent.js

@@ -26,14 +26,14 @@ var pump = require('pump')
 var randomIterate = require('random-iterate')
 var reemit = require('re-emitter')
 var sha1 = require('simple-sha1')
-var Swarm = require('bittorrent-swarm')
 var uniq = require('uniq')
 var ut_metadata = require('ut_metadata')
 var ut_pex = require('ut_pex') // browser exclude
 
 var File = require('./file')
 var RarityMap = require('./rarity-map')
 var Server = require('./server') // browser exclude
+var Swarm = require('./swarm')
 
 var MAX_BLOCK_LENGTH = 128 * 1024
 var PIECE_TIMEOUT = 30000