Whitehall::Uploader::AttachmentCache.default_root_directory = if Rails.env.production?
  "/mnt/apps/whitehall-admin/attachment-cache"
else
  Rails.root.join("tmp", "cache", "attachment-cache")
end

Whitehall::Uploader::AttachmentCache.default_root_directory = Rails.root.join("attachment-cache")

Use same location for attachment cache on all environments.
Use same location for attachment cache on all environments.

The folder /mnt/apps/whitehall-admin/attachment-cache isn't writable
on staging or production, so the location needed to change.  Instead
of configuring this within the app, we are instead symlinking a set
location (<app-root>/attachment-cache) on deployment.
