Remember when D.C. Mayor Adrian Fenty said he was expecting 4 million people to show up for Inauguration Day, but some federal officials retorted that his number was way too high? Well today the Post reports that estimates appear to be being revised to more like 2 million — which is still way, way more than the 400,000 or so who attended the 2005 inauguration of President Bush, but at least it doesn’t quite put…