Fix computed-balances controller reference

app/scripts/metamask-controller.js

@@ -20,7 +20,7 @@ const BlacklistController = require('./controllers/blacklist')
 const MessageManager = require('./lib/message-manager')
 const PersonalMessageManager = require('./lib/personal-message-manager')
 const TransactionController = require('./controllers/transactions')
-const BalancesController = require('./controllers/balances')
+const BalancesController = require('./controllers/computed-balances')
 const ConfigManager = require('./lib/config-manager')
 const nodeify = require('./lib/nodeify')
 const accountImporter = require('./account-import-strategies')