Jeffrey Adam Gutt — the single dad with the tattoo sleeves — sentThe X Factor judges into an ecstatic tizzy when he put his gravel-voiced spin on Leonard Cohen’s “Hallelujah.” L.A. Reid called him “Unbelievable,” Britney Spears dubbed his voice, “Soothing and unique.” The best part?Simon Cowell said it was, “One of the most brilliant auditions I’ve heard.” Wow.