Fix link to owner of group and team in admin interface (4.2)

Created by: jojosch

backported #3017 to 4.2-stable

app/views/admin/groups/index.html.haml

@@ -28,7 +28,7 @@
       %td= group.path
       %td= group.projects.count
       %td
-        = link_to group.owner_name, admin_user_path(group.owner_id)
+        = link_to group.owner_name, admin_user_path(group.owner)
       %td.bgred
         = link_to 'Rename', edit_admin_group_path(group), id: "edit_#{dom_id(group)}", class: "btn btn-small"
         = link_to 'Destroy', [:admin, group], confirm: "REMOVE #{group.name}? Are you sure?", method: :delete, class: "btn btn-small btn-remove"