A federal jury in Chicago convicted R. Kelly on Wednesday of producing child pornography and enticing girls for sex after a month-long trial in his hometown, delivering another legal blow to the Grammy Award winning singer who was once one of the world’s biggest R&B stars.Prosecutors won convictions on six of the 13 counts against him, with many of the convictions carrying long mandatory sentences. But the government lost the marquee count — that Kelly and his then-business manager successfully rigged his state child …