Ensure that ORDER BY clauses from default scopes are not included in total_count queries in AR 3.1.beta1

see: https://github.com/rails/rails/issues/406

lib/kaminari/models/active_record_relation_methods.rb

@@ -13,6 +13,8 @@ module Kaminari
       def total_count #:nodoc:
         # #count overrides the #select which could include generated columns referenced in #order, so skip #order here, where it's irrelevant to the result anyway
         c = except(:offset, :limit, :order)
+        # a workaround for 3.1.beta1 bug. see: https://github.com/rails/rails/issues/406
+        c = c.reorder nil
         # Remove includes only if they are irrelevant
         c = c.except(:includes) unless references_eager_loaded_tables?
         # .group returns an OrderdHash that responds to #count