Fix that JSON and XML exception responses should give the HTTP error message for their status, by default, not the message from the underlying exception
"rails" -> "Rails" [ci skip]
Require different core extensions correctly.

The begin rescue block is specifically to catch LoadError while loading
i18n gem. Other core extensions, under active support, should be
required outside of the begin rescue block.
rails -> Rails [ci skip]
remove redundant var
remove variable and fix warning