removed inconclusive proof for Google CDN caching

Perhaps the rise in [AngularJS](http://angularjs.org/)'s popularity be the real cause for the rise in popularity in ajax.googleapis.com?  Or maybe "[Sites using Google Libraries API](http://httparchive.org/trends.php#perGlibs)" rise is caused by "[Sites with Custom Fonts](http://httparchive.org/trends.php#perFonts)"?  Perhaps a revisit to see if [hitting the version lottery](https://github.com/h5bp/html5-boilerplate/pull/1327#issuecomment-14857390) is in order, but I doubt it will prove it is worth mentioning "increases the odds of having a copy of the library in your user's browser cache".

Even though I'm involved with [jsDelivr CDN](http://www.jsdelivr.com/), and I see alot of [cdnjs](http://cdnjs.com/) usage in the wild, I conclude Google's CDN is the best to use for h5bp.  But please, an extra 1% chance of hitting cache isn't really worth it IMHO.