logtree: rename payload to leveledpayload

Test Plan: Refactor, covered by tests.

X-Origin-Diff: phab/D639
GitOrigin-RevId: 6c268c8b437a93c97720f110dbc9c39e95402648
diff --git a/core/pkg/logtree/logtree_access.go b/core/pkg/logtree/logtree_access.go
index 045f105..c10aa7b 100644
--- a/core/pkg/logtree/logtree_access.go
+++ b/core/pkg/logtree/logtree_access.go
@@ -78,7 +78,7 @@
 }
 
 type LogEntry struct {
-	*Payload
+	*LeveledPayload
 	DN DN
 }
 
@@ -146,7 +146,7 @@
 	lr := &LogReader{}
 	lr.Backlog = make([]*LogEntry, len(entries))
 	for i, entry := range entries {
-		lr.Backlog[i] = &LogEntry{Payload: entry.payload, DN: entry.origin}
+		lr.Backlog[i] = &LogEntry{LeveledPayload: entry.leveled, DN: entry.origin}
 	}
 	if stream {
 		lr.Stream = sub.dataC