Break out the asset path rewrite in case plugins wish to put the asset id someplace other than the query string.

Source Code

# File action_view/helpers/asset_tag_helper.rb, line 511
def rewrite_asset_path(source)
  asset_id = rails_asset_id(source)
  if asset_id.blank?
    source
  else
    source + "?#{asset_id}"
  end
end