External links: prevent selflinking

In live blogs it is common for a journalist to link towards an older update. This prevents those links to be turned into left-column cards.

Thanks @papalozarou for notifying it (cf screenshot of http://www.theguardian.com/science/2012/jun/05/transit-of-venus-live-coverage).

![screen shot 2013-08-30 at 14 58 14](https://f.cloud.github.com/assets/85783/1057822/405a6f92-117c-11e3-8027-6a229e3b3976.PNG)

![ ](http://s1.developerslife.ru/public/images/gifs/77998a02-f2d0-4b40-9a84-02ecf04c3381.gif)