We are using the following warnings in the Katello controller code:

https://github.com/Katello/katello/blob/master/app/controllers/katello/api/v2/repositories_controller.rb#L222-L224

This commit looks like it silenced it:

https://github.com/theforeman/foreman/commit/0fd467c844fd200b5da72a0c670a5ac2bd4a61d6

This issue looks to log the warning to Rails for the API calls we care about and ignore the deprecated Rails calls we do not care about.