INSERT OVERWRITE with empty result set does not clear transactional table

The following query:

INSERT OVERWRITE TABLE t SELECT 1 WHERE FALSE

should serve to truncate a table by producing an empty base data directory. In fact no new base directory is created, so the table is not cleared. (at least with an insert_only table, I didn't test full-ACID)

This bug does not seem to happen with non-transactional tables.