LU-6056 tests: fix -hsm wrong usage of bash's local built-in

LU-6056 tests: fix -hsm wrong usage of bash's local built-in

In sanity-hsm test script, there were several places where the
bash's local built-in was used with assignments from a command
substitution and command's exit code was tested after.

This is a wrong usage since the 'local' builtin does not propagate
the exit code.

Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: I4257e55ec61ed0c4e48812407b5cf82ab316b701
Reviewed-on: http://review.whamcloud.com/13159
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>