Comment out active_record.mass_assignment_sanitizer config since it's
not compatible with Rails 4.1
Revert "Remove whitelist_attributes setting in config as it was causing failures"

This reverts commit b6126f9681aca325d88a1ce18d6a7fc028dbbe9d.

We'll comment out the config instead of deleting it altogether.
Comment out active_record.whitelist_attributes config since it's not
compatible with rails 4.1