sql/v1tov2: path_full_stem(path) is unique per-bucket

sql/v1tov2.sql

@@ -270,8 +270,8 @@ ALTER TABLE object
     DROP COLUMN dir,
     DROP COLUMN random_key;
 
-CREATE UNIQUE INDEX object_path_full_stem_path_key
-    ON object (path_full_stem(path))
+CREATE UNIQUE INDEX object_bucket_path_full_stem_path_key
+    ON object (bucket, path_full_stem(path))
     WHERE enforce_unique_name;
 
 CREATE FUNCTION _object_before_insert_normalize_path() RETURNS trigger