MRP-334 test: sanity 162 not properly handle DIR values

The test fails when path values have trailing slash,
for example: DIR=/mnt/lustre/
Added validation function which at the moment processes
next parameters: DIR, DIR1, DIR2, MOUNT, MOUNT1, MOUNT2

Signed-off-by: Kyrylo Shatskyy <kyrylo_shatskyy@xyratex.com>
Xyratex-bug-id: MRP-334
Change-Id: I10d283a977f4dbddabd75a6d4d507e700dc0c040
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/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>