LU-7130 test: sanity/162 doesn't handle DIR values properly

LU-7130 test: sanity/162 doesn't handle DIR values properly

The test fails when path values have trailing slash,
e.g. DIR=/mnt/lustre/

The patch adds validation which at the moment processes
these parameters-DIR, DIR1, DIR2, MOUNT, MOUNT1, MOUNT2.

Change-Id: Ief85e8798911cb67b4dafce985a9e4ef56cc26a4
Signed-off-by: Kyrylo Shatskyy <kyrylo.shatskyy@seagate.com>
Signed-off-by: Parinay Kondekar <parinay.kondekar@seagate.com>
Seagate-bug-id: MRP-334
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/#/c/269
Tested-by: Jenkins
Reviewed-by: Andrew Perepechko <Andrew_Perepechko@xyratex.com>
Reviewed-by: Alexander Lezhoev <Alexander_Lezhoev@xyratex.com>
Tested-by: Alexander Lezhoev <Alexander_Lezhoev@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>
Reviewed-on: http://review.whamcloud.com/16358
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>