LU-9123 test: correct setstripe options in layout test

LU-9123 test: correct setstripe options in layout test

In llapi_layout_test.c use '-S' instead of the now removed '-s'
option to lfs setstripe

Test-Parameters: trivial

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I74f020f29b1a274e6fe63aac29685b88e541e649
Reviewed-on: https://review.whamcloud.com/25471
Tested-by: Jenkins
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>