Fix issue with normalize.css setting content-box sizing on type="search"

See this [JsFiddle](http://jsfiddle.net/paultyng/saXsx/) for visual demonstration.

Normalize overrides the * rule and sets the `box-sizing` to `content-box` so overriding back to `border-box` in *forms.less*.  Not sure if you would just prefer the edit in the normalize file or not.