CHICAGO — With less than two months to go until ex-R&B superstar R. Kelly and two of his former associates go on trial in Chicago, the sparks are starting to fly. But the most recent legal spat hasn’t involved prosecutors at all — it’s between the defendants. On Wednesday, lawyers for former Kelly manager Derrel McDavid blasted claims by the singer’s attorney that there may be a conflict of interest with McDavid’s legal team as “either woefully uninformed or purposely mendacious.” The response also criticized Kelly’s lawyer, Jennifer Bonjean, for what they called a “disingenuous” attempt to li…