fix result type

lib/expressapp.js

@@ -290,9 +290,9 @@ ExpressApp.prototype.start = function(opts, cb) {
 
   router.post('/v1/broadcast_raw/', function(req, res) {
     getServerWithAuth(req, res, function(server) {
-      server.broadcastRawTx(req.body, function(err, txp) {
+      server.broadcastRawTx(req.body, function(err, txid) {
         if (err) return returnError(err, res, req);
-        res.json(txp);
+        res.json(txid);
         res.end();
       });
     });