use attachment secure_url for Attachemnt page

app/views/projects/files.html.haml

@@ -9,7 +9,7 @@
     - @notes.each do |note|
       %tr
         %td
-          %a{href: note.attachment.url}
+          = link_to note.attachment.secure_url, target: "_blank" do
             = image_tag gravatar_icon(note.author_email), class: "avatar s24"
             = note.attachment_identifier
         %td