Fix configuring a cache store with ActiveSupport::OrderedOptions

9845cd63 broke configuring a cache store like so:

    config.cache_store = :redis_cache_store, config_for("redis/cache")

Rails::Application#config_for returns an ActiveSupport::OrderedOptions. By default, the Array#extract_options! core extension won't extract instances of Hash subclasses. Add ActiveSupport::OrderedOptions#extractable_options? and have it return true to fix.

activesupport/lib/active_support/ordered_options.rb

@@ -56,6 +56,10 @@ def method_missing(name, *args)
     def respond_to_missing?(name, include_private)
       true
     end
+
+    def extractable_options?
+      true
+    end
   end
 
   # +InheritableOptions+ provides a constructor to build an +OrderedOptions+

activesupport/test/cache/cache_store_setting_test.rb

@@ -65,4 +65,13 @@ def test_object_assigned_fragment_cache_store
     assert_kind_of(ActiveSupport::Cache::FileStore, store)
     assert_equal "/path/to/cache/directory", store.cache_path
   end
+
+  def test_redis_cache_store_with_ordered_options
+    options = ActiveSupport::OrderedOptions.new
+    options.update namespace: "foo"
+
+    store = ActiveSupport::Cache.lookup_store :redis_cache_store, options
+    assert_kind_of(ActiveSupport::Cache::RedisCacheStore, store)
+    assert_equal "foo", store.options[:namespace]
+  end
 end