remove useless class_eval

activerecord/lib/active_record/base.rb

@@ -2121,9 +2121,7 @@ MSG
           send("#{att}=", value) if respond_to?("#{att}=")
         end
       end
-  end
 
-  Base.class_eval do
     include ActiveRecord::Persistence
     extend ActiveModel::Naming
     extend QueryCache::ClassMethods