Go straight to the class for asset_host

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1299 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -110,7 +110,7 @@ def compute_public_path(source, dir, ext)
           source = "/#{dir}/#{source}" unless source.include?("/")
           source = "#{source}.#{ext}" unless source.include?(".")
           source = "#{@request.relative_url_root}#{source}"
-          @controller.asset_host + source
+          ActionController::Base.asset_host + source
         end
     end
   end