By Matt Hladik A reportedly agreed-upon deal between defensive end Randy Gregory and the Dallas Cowboys fell through, and owner Jerry Jones is apparently not happy. CBS Sports’ Patrik Walker reported moments ago that Jones is “livid” that the team attempted to tweak the contract after Gregory had already agreed to sign. This action led to Gregory eventually spurning the Cowboys for the Broncos. The Cowboys are no strangers to occasional front-office dysfunction, and it seems like Stephen Jones, Jerry’s son and the team’s VP and de facto GM, is the person to blame here. That’s what most Cowboys…