remove redundant code for func epoch in create_partition_time

sql/functions/create_partition_time.sql

@@ -46,8 +46,6 @@ v_sub_timestamp_max             timestamptz;
 v_sub_timestamp_min             timestamptz;
 v_template_table                text;
 v_time                          timestamptz;
-v_partition_id_start            bigint;
-v_partition_id_end              bigint;
 v_partition_text_start          text;
 v_partition_text_end            text;
 
@@ -221,7 +219,7 @@ FOREACH v_time IN ARRAY p_partition_times LOOP
         PERFORM @[email protected]_template_properties(p_parent_table, v_parent_schema, v_partition_name);
     END IF;
 
-    IF v_epoch = 'none' THEN
+    IF v_epoch IN ('none', 'func') THEN
         -- Attach with normal, time-based values for built-in constraint
         IF v_time_encoder IS NULL THEN
             EXECUTE format('ALTER TABLE %I.%I ATTACH PARTITION %I.%I FOR VALUES FROM (%L) TO (%L)'
@@ -243,17 +241,6 @@ FOREACH v_time IN ARRAY p_partition_times LOOP
                 , v_partition_text_start
                 , v_partition_text_end);
         END IF;
-    ELSIF v_epoch = 'func' THEN
-        EXECUTE format('SELECT %s(%L)', v_time_encoder, v_partition_timestamp_start) INTO v_partition_id_start;
-        EXECUTE format('SELECT %s(%L)', v_time_encoder, v_partition_timestamp_end) INTO v_partition_id_end;
-
-        EXECUTE format('ALTER TABLE %I.%I ATTACH PARTITION %I.%I FOR VALUES FROM (%L) TO (%L)'
-            , v_parent_schema
-            , v_parent_tablename
-            , v_parent_schema
-            , v_partition_name
-            , v_partition_id_start
-            , v_partition_id_end);
     ELSE
         -- Must attach with integer based values for built-in constraint and epoch
         IF v_epoch = 'seconds' THEN