mkfs: removed unused dft var from open_config_file

This should have been removed when I removed the dft->type
tracking.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
3 files changed