woothemes/woocommerce — pull request #997 by GeertDD (2012-05-03 11:52:36+00:00)
Title: Apply the filter "plugin_locale" to the locale for loading language files from the WP_LANG_DIR

The `load_plugin_textdomain()` function does this too. Since we are loading language files for a plugin also, it only makes sense to include the same filter.