LU-3183 tests: sanity test_27f dd to the wrong file

typo in the output file in dd.

Signed-off-by: Minh Diep <minh.diep@intel.com>
Change-Id: I63c5627ed766b92b1446b8f8082017b0e804dbbe
Reviewed-on: http://review.whamcloud.com/6084
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>