RSS Feed with Unicode Alias fails to validate [#33478]

Tracker code : # 33478

Joomla RSS feed contains invalid UTF-8 characters in URL, these fail validation and prevent certain libraries from using the feeds.
Assuming you have a category ID 173 which contains an article with an unicode alias, with an url like:
http://example.com/index.php?option=com_content&view=category&id=173&format=feed&type=rss&lang=en
http://validator.w3.org/feed will return the following errors:
This feed does not validate.
line 25, column 101: link must be a full and valid URL: http://example.com/company/news/1185-soso-ibérica-opens-new-fishing-garden
line 26, column 120: guid must be a full URL, unless isPermaLink attribute is false: http://example.com/company/news/1185-soso-ibérica-opens-new-fishing-garden

How to reproduce the problem and/or test the patch::
Setup a Joomla 3.2.3 with unicode aliases enabled in the global configuration; Create an article with a unicode character in the alias e.g. 'à' Run the rss feed through http://validator.w3.org/feed It will fail to validate both <link> (link) and <guid> (guid)