Remove spree require that is not needed in OFN

lib/spree/core.rb

@@ -40,14 +40,12 @@ module Spree
   end
 end
 
-require 'spree/core/version'
 require 'spree/core/engine'
 
 require 'spree/i18n'
 require 'spree/money'
 
 require 'spree/core/delegate_belongs_to'
-require 'spree/core/ext/active_record'
 require 'spree/core/permalinks'
 require 'spree/core/token_resource'
 require 'spree/core/calculated_adjustments'