Preserve selected locale when downloading mailer preview EML

Author: fatkodima

railties/lib/rails/templates/rails/mailers/email.html.erb

@@ -156,7 +156,7 @@
     <% end %>
 
     <dt>EML File:</dt>
-    <dd><%= link_to "Download", action: :download %></dd>
+    <dd><%= link_to "Download", action: :download, locale: params[:locale] %></dd>
   </dl>
 </header>