Modify exception_handler for a string error like AuthenticationError#73

jerel merged 2 commits intodjango-json-api:developdjango-json-api/django-rest-framework-json-api:developfrom

hnakamur:modify_exception_handler_for_authentication_errorhnakamur/django-rest-framework-json-api:modify_exception_handler_for_authentication_errorCopy head branch name to clipboard