Fix btn margin for commit show page

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

app/views/projects/commit/_commit_box.html.haml

@@ -5,7 +5,7 @@
         %i.icon-comment
         = @notes_count
     .pull-left.btn-group
-      %a.btn.grouped.dropdown-toggle{ data: {toggle: :dropdown} }
+      %a.btn.btn-grouped.dropdown-toggle{ data: {toggle: :dropdown} }
         %i.icon-download-alt
         Download as
         %span.caret