add cassandra2 (#6582)

weed/command/scaffold/filer.toml

@@ -139,12 +139,13 @@ connection_max_lifetime_seconds = 0
 enableUpsert = true
 upsertQuery = """UPSERT INTO "%[1]s" (dirhash,name,directory,meta) VALUES($1,$2,$3,$4)"""
 
-[cassandra]
+[cassandra2]
 # CREATE TABLE filemeta (
+#    dirhash bigint,
 #    directory varchar,
 #    name varchar,
 #    meta blob,
-#    PRIMARY KEY (directory, name)
+#    PRIMARY KEY ((dirhash, directory), name)
 # ) WITH CLUSTERING ORDER BY (name ASC);
 enabled = false
 keyspace = "seaweedfs"