Life's about curveballs. Case in point: no one expected Clint Eastwood to debate an empty chair at the Republican National Convention. Likewise no one likely thought his first acting role since 2008’s "Grand Torino" (SEE our review) would be in something so draggy and lightweight as “Trouble with the Curve. ”Eastwood's Gus is all growl, stubbornness and agitation--look out, furniture. A baseball talent scout, he