LU-2610 tests: Reenable sanity/40 for ZFS

LU-2610 tests: Reenable sanity/40 for ZFS

Due to fix by LU-2804 change c8d5aa14e50be2a85491783f169a8f4e646b9594
This test should no longer be skipped for ZFS and should pass.

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: I1e464b8874b0968f038ec4c88c7b24d2fb03207b
Reviewed-on: http://review.whamcloud.com/12153
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>