LU-9288 tests: t-f to check if ZFS module is loaded

LU-9288 tests: t-f to check if ZFS module is loaded

it's possible that ZFS modules are missing in /lib/modules/ in
a development environment. if so, then modprobe fails preventing
regular testing. t-f can check whether ZFS module is loaded already.

Change-Id: Ie871be7a9af3c15968de8b5d8a8c99b3e1cb4274
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: https://review.whamcloud.com/26334
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>