Unwanted focus outline on modal windows.

Created by: frankdejonge

At first I though it was a new style thing, which startled me..... But then compared to how other people saw the modal windows and spotted the 'bug'. When on Mac (other linux people don't have it) there's a focus outline on the modal windows, both the modal window (http://d.pr/i/HmAE), and the button spawning it (http://d.pr/i/K3O9) are affected.

I was able to remove it by adding the following bit of css into the page through the inspector:

:focus{
    outline: none;
}

But I reckon this is way to intrusive to ever get a place in the reset.less, hence that I'm filing an issue instead of a pull-request.