fix(mustCollect): place mustCollect setting to the right place

Author: peteyycz

lib/providers/httpTransaction/wraps/http.Server.prototype.js

@@ -64,8 +64,6 @@ function wrapListener(listener, collector, config) {
      */
     function instrumentedFinish () {
 
-      mustCollect = mustCollect || response.statusCode > 399;
-
       var collectorDataBag = {
         mustCollect: mustCollect,
         id: requestId,
@@ -86,6 +84,7 @@ function wrapListener(listener, collector, config) {
 
     response.writeHead = function () {
       serverSendTime = microtime.now();
+      mustCollect = mustCollect || response.statusCode > 399;
 
       /* Service name may be unavailable due to uninitialized reporter */
       var serviceName = collector.getService();