Rails 5: Skip invalid Mime::Type tests
Rails 5: Skip invalid Mime::Type tests

`ActionController` will now raise an "Unknown Content-Type" error
before our own methods are ever called.

Signed-off-by: Alex Coles <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@alexbcoles.com>

apotonick/roar-rails