current oauth2.0 server's error response body format is:
- error (invalid_client, unauthorized_client, etc)
- error_description (..)

i need to customize this error response such as facebook for body:
- {error:{code:'', message:'', type:''}}

so it'will be consistent with our api server error response.

do i need custom
- OAuth2ExceptionSerializer
- OAuth2ExceptionDeserializer
- DefaultOAuth2ExceptionRenderer
- or convertor?

any help will be appriciated.