Fix crash on feeds containing posts with inline images (e.g. data uri's)

Feeds like [these](http://r-norberg.blogspot.co.il/feeds/posts/default) [two](http://jeffreyhorner.blogpsot.com/atom.xml) inline their images using [Data URI's](http://en.wikipedia.org/wiki/Data_URI_scheme), but this causes seg faluts in apache ( and even in php cli in testing) because of the current regex created via attributeRegex.

This two liner fixes the crash while allowing feedwordpress to support these kinds of feeds.