The CMT Awards paid tribute to the late Gregg Allman last night as they opened the show with a performance of “Midnight Rider” led by Darius Rucker, Jason Aldean and Lady Antebellum’s Charles Kelley singing an acapella version of the song. When the full band emerged, Allman’s bandmate Derek Trucks emerged to play slide guitar on the song as the group rounded out a touching tribute to Allman…