Merge branch 'ux/closed-message' into 'master'

Fix ux issue with "This issue will be closed automatically" message

1. Make a nice box for "issue will be closed automatically" message
2. move it below emoji navbar. Otherwise looks wierd. 

Fixes #4134 

# Before
![Screenshot_2015-12-17_00.01.03](/uploads/2a24de77f76ce8a8b61ebabd3a02c83a/Screenshot_2015-12-17_00.01.03.png)

# After

![Screenshot_2015-12-17_00.03.08](/uploads/ccd21b87b7509e79773fabd179bef4aa/Screenshot_2015-12-17_00.03.08.png)


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

See merge request !2129

app/assets/stylesheets/pages/issues.scss

@@ -141,11 +141,6 @@ form.edit-issue {
   }
 }
-.issue-closed-by-widget {
-  padding: 16px 0;
-  margin: 0px;
-}
-
 .issue-form .select2-container {
   width: 250px !important;
 }

app/views/projects/issues/_closed_by_box.html.haml

-.issue-closed-by-widget
-  = icon('check')
+.issue-closed-by-widget.gray-content-block.second-block.white
   This issue will be closed automatically when merge request #{markdown(merge_requests_sentence(@closed_by_merge_requests), pipeline: :gfm)} is accepted.

app/views/projects/issues/_discussion.html.haml

@@ -8,5 +8,8 @@
 .gray-content-block.second-block.oneline-block
   = render 'votes/votes_block', votable: @issue
+- if @closed_by_merge_requests.present?
+  = render 'projects/issues/closed_by_box'
+
 #notes
   = render 'projects/notes/notes_with_form'

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

@@ -54,8 +54,6 @@
             .merge-requests
               = render 'merge_requests'
-        - if @closed_by_merge_requests.present?
-          = render 'projects/issues/closed_by_box'
         .issue-discussion
           = render 'projects/issues/discussion'