When running examples/c/ex_backup_block/ex_backup_block successfully, the test leaves two directories behind instead of cleaning them up.

There is a function compare_backups which typically compares an incremental against a full backup. There is a special comparison value, 0, against the main database. That comparison is done at the end of the run.

In compare_backups, the cleanup is conditional on i != 0 because that cleanup command removes a DIR.FULL.N and DIR.INCR.N.

The program should be fixed so that on success with 0 it just removes in DIR.INCR.0 directory and the end of main cleans up/removes the database directory.