http: Handle end only when stream is not dumped

This fixes regression introduced in some cases by 8bf0c15

lib/http.js

@@ -160,7 +160,9 @@ function parserOnMessageComplete() {
       stream._readableState.onread(null, null);
   }
 
-  if (!stream._readableState.endEmitted && !parser.incoming._pendings.length) {
+  if (stream &&
+      !stream._readableState.endEmitted &&
+      !parser.incoming._pendings.length) {
     // For emit end event
     stream._readableState.onread(null, null);
   }