Show MR accept info only if merge request is open

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

app/views/projects/merge_requests/_show.html.haml

@@ -2,10 +2,11 @@
   = render "projects/merge_requests/show/mr_title"
   = render "projects/merge_requests/show/how_to_merge"
   = render "projects/merge_requests/show/mr_box"
-  - if @merge_request.source_branch_exists? && @merge_request.target_branch_exists?
-    = render "projects/merge_requests/show/mr_accept"
-  - else
-    = render "projects/merge_requests/show/no_accept"
+  - if @merge_request.opened?
+    - if @merge_request.source_branch_exists? && @merge_request.target_branch_exists?
+      = render "projects/merge_requests/show/mr_accept"
+    - else
+      = render "projects/merge_requests/show/no_accept"
   - if @merge_request.source_project.gitlab_ci?
     = render "projects/merge_requests/show/mr_ci"
   = render "projects/merge_requests/show/commits"