fix up empty context

lib/crawler.js

@@ -115,6 +115,7 @@ class Crawler {
         request.crawler = self;
         request.crawlerName = options.name;
         requestBox[0] = request;
+        request.context = request.context || {};
         request.promises = [];
         return request;
       })
@@ -347,9 +348,8 @@ class Crawler {
 
   _createQueuable(request) {
     // Create a new request data structure that has just the things we should queue
-    const queuable = new Request(request.type, request.url);
+    const queuable = new Request(request.type, request.url, request.context);
     queuable.attemptCount = request.attemptCount;
-    queuable.context = request.context;
     queuable.force = request.force;
     queuable.subType = request.subType;
     return queuable;