attachment.present? calls AWS API

[Paxa]

Not sure if that's expected behavior, but when we call file.present? it calls AWS API (HEAD request to AWS)

if attachment.present? # this makes API call (which is slow)
  return attachment.url # this is generated with presigned URL feature
end

basically in code we just want to know if there is any file in a model, and not expecting .present? take half second

[shanecav84]

This was introduced to fix #1926 (in 2d1af56). This also effected CarrierWave::Uploader::Proxy#blank? which calls to CarrierWave::Storage::Fog::File#empty?. Since in ActiveSupport present? calls !blank? which calls empty?, then calling present? on an uploader calls the AWS API.

The change to CarrierWave::Storage::Fog::File makes sense to me but I think the change to CarrierWave::Uploader::Proxy needs to be addressed. A quick suggestion is to change CarrierWave::Uploader::Proxy#blank? to check @file.nil?.