Revert "Make sure render json: ..., each_serializer: ... is working with Enumerables"

This reverts commit 90343cea4d.

lib/action_controller/serialization.rb

@@ -87,7 +87,7 @@ module ActionController
       if serializer = options.fetch(:serializer, default_serializer(resource))
         options[:scope] = serialization_scope unless options.has_key?(:scope)
 
-        if resource.respond_to?(:each)
+        if resource.respond_to?(:to_ary)
           options[:resource_name] = controller_name 
           options[:namespace] = namespace_for_serializer if namespace_for_serializer
         end

lib/active_model/serializer.rb

@@ -56,7 +56,7 @@ end
       attr_reader :key_format
 
       def serializer_for(resource, options = {})
-        if resource.respond_to?(:each)
+        if resource.respond_to?(:to_ary)
           if Object.constants.include?(:ArraySerializer)
             ::ArraySerializer
           else