Last year, the great Memphis rapper Young Dolph was murdered at the age of 36; it’s an incalculable loss for rap music. There haven’t been a lot of saccharine Dolph tributes, possibly because Dolph was never a saccharine rapper. Instead, Dolph tributes have generally taken the form of tracks like “Long Live Dolph,” a song that the frequent Dolph collaborator Gucci Mane released last year — songs that stick to the same swaggering street-rap blueprint that Dolph himself always used. That’s definitely the case with Gucci’s new single “Blood All On It,” which features a posthumous Dolph verse and an appearance from Dolph’s cousin and rap partner Key Glock.