Revert "remember to downcase on registration"

This reverts commit 0c0444c078.

app/controllers/devise/registrations_controller.rb

@@ -68,9 +68,6 @@ class Devise::RegistrationsController < ApplicationController
     # temporary session data to the newly created user.
     def build_resource(hash=nil)
       hash ||= params[resource_name] || {}
-      if Devise.case_insensitive_keys
-        Devise.authentication_keys.each { |k| hash[k].try(:downcase!) }
-      end
       self.resource = resource_class.new_with_session(hash, session)
     end