Fix closed merge request scope at milestone page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/views/projects/milestones/show.html.haml

@@ -86,7 +86,7 @@
       .col-md-3
         = render('merge_requests', title: 'Waiting for merge (open and assigned)', merge_requests: @merge_requests.opened.assigned, id: 'ongoing')
       .col-md-3
-        = render('merge_requests', title: 'Rejected (closed)', merge_requests: @merge_requests.rejected, id: 'closed')
+        = render('merge_requests', title: 'Rejected (closed)', merge_requests: @merge_requests.closed, id: 'closed')
       .col-md-3
         .panel.panel-primary
           .panel-heading Merged