LU-8251 tests: Delete only test files for sanityn

LU-8251 tests: Delete only test files for sanityn

For sanityn tests_40* to tests_47* replacing
rm -r $DIR1/* with rm -rf $DIR/$tfile* so that
only the tests files are deleted and not all the
data contained in $DIR1

Test-Parameters: trivial testlist=sanityn,sanityn,sanityn,sanityn
Signed-off-by: Saurabh Tandan <saurabh.tandan@intel.com>
Change-Id: I353f9d40c5ee4ee99e7cce90fb61ce9f6d5b8567
Reviewed-on: http://review.whamcloud.com/20718
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>