Remove backend.Tree

backend/paths.go

@@ -6,7 +6,6 @@ import "os"
 var Paths = struct {
 	Data      string
 	Snapshots string
-	Trees     string
 	Index     string
 	Locks     string
 	Keys      string
@@ -16,7 +15,6 @@ var Paths = struct {
 }{
 	"data",
 	"snapshots",
-	"trees",
 	"index",
 	"locks",
 	"keys",