Dolly Parton appears on Kesha’s next album Rainbow as a guest vocalist the pop singer’s version of “Old Flames (Can’t Hold a Candle to You).” Kesha’s mother Pebe Sebert and Hugh Moffatt co-wrote the song, which was a No. 1 hit from Parton’s album Dolly, Dolly, Dolly in 1980. Originally a hit for Joe Sun,…