rails/rails — pull request #17366 by y-yagi (2014-10-23 10:20:39+00:00)
Title: Modify config_for to return HashWithIndifferentAccess

I want to return HashWithIndifferentAccess instead of Hash.

For example, When I use `config_for` for `exception_notification`, `exception_notification` use symbols to get parameter.
Threfore, I need conversion processing.