Default RSS Widget feed needs to be updated

[john-henry]

The older RSS feed from ExpressionEngine is no longer accessible and needs to be updated in the RSS widget from

'url' => 'http://expressionengine.com/feeds/rss/eeblog/',

to

'url' => 'http://ellislab.com/blog/rss-feed',

This is also the cause of the PHP errors when adding widget for first time as there is no method for checking if feed does not exist.

[mrtopher]

Thanks for the merge request. Works like a charm now.