LU-9379 tests: Improve get_version to handle empty return value

LU-9379 tests: Improve get_version to handle empty return value

replay-vbr fails when get_version() returns empty value to
either pre/post variable. This patch modifies replay-vbr
get_version() by returning '-1' in case getobjversion fails.

This patch also adds chk_get_version(). Which is a wrapper
to get_version(). chk_get_version() helps in verifying
return code of get_version().

Signed-off-by: Arshad Hussain <arshad.hussain@seagate.com>
Reviewed-by: Jadhav Vikram <jadhav.vikram@seagate.com>
Reviewed-by: Ujjwal Lanjewar <ujjwal.lanjewar@seagate.com>
Reviewed-by: Parinay Kondekar <parinay.kondekar@seagate.com>
Seagate-bug-id: MRP-3589
Test-Parameters: trivial testlist=replay-vbr
Change-Id: Ief4d42d1433d890086122218ff6f53d4ea9489e1
Reviewed-on: https://review.whamcloud.com/26767
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>