IOWA CITY, Iowa — An Iowa man’s use of a smartphone application to get legal help in the middle of the night proved key in getting his drunken driving conviction overturned.Davenport police violated Craig Hermann’s rights during his 2014 arrest, when a breath test showed that his blood-alcohol content was more than twice the legal limit, the Iowa Court of Appeals ruled Wednesday.A West Des Moines law firm, Rehkemper & Lindholm PLC, developed the Oh Crap! App to allow users to know their rights during …