The Republican nominee for governor in Iowa pulled back the curtain for Fox News Digital on the time he went viral for stumping Barack Obama at a 2009 town hall centered on the then-president's namesake legislation.Zach Lahn pulled off an upset victory Tuesday night when he defeated Trump-backed Republican Rep. Randy Feenstra, R-Iowa, for the party's nomination for governor.But 17 years ago, when he was a student at the University of Colorado Bo…