Always serve thumbnails with disposition: attachment (#38417).

Patch by Holger Just.


git-svn-id: https://svn.redmine.org/redmine/trunk@22294 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/controllers/attachments_controller.rb

@@ -89,7 +89,7 @@ class AttachmentsController < ApplicationController
           tbnail,
           :filename => filename_for_content_disposition(@attachment.filename),
           :type => detect_content_type(@attachment, true),
-          :disposition => 'inline')
+          :disposition => 'attachment')
       end
     else
       # No thumbnail for the attachment or thumbnail could not be created