LU-9494 test: Improve message for skipping tests

LU-9494 test: Improve message for skipping tests

Modify skip messages for consistency and clarity.

Signed-off-by: Ruth Klundt <rklundt@sandia.gov>
Change-Id: I44ced56e67aa63ed84da6a15c88282bc3ff19332
Test-Parameters: trivial testlist=sanity
Reviewed-on: https://review.whamcloud.com/27350
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Wei Liu <wei3.liu@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>