Billy Ray Cyrus is fuming because he has to sign over any credits and future royalties for songs he wrote with his ex, Firerose, as part of their divorce deal, an insider tells RadarOnline.com. The tipster claimed: “Even that was too much for Billy Ray. If he could have left her with nothing, he would have – the split was that bitter and acrimonious. To him, she’s nothing but a con woman.” The severed spouses finally reached a divorce deal ending their blink-and-you-missed-it seven-month marriage. Despite his qualms over the agreement, the Achy Breaky Heart singer will not have to give his ex …