LU-9890 osd-zfs: dmu_objset_own/disown changes

LU-9890 osd-zfs: dmu_objset_own/disown changes

ZFS 0.8.0 will introduce ZFS encryption. The interfaces
to 'dmu_objset_own' and 'dmu_objset_disown' have changed.
Add configure checks to determine which versions of these
functions are available and call them appropriately.

Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Test-Parameters: trivial ostfilesystemtype=zfs mdtfilesystemtype=zfs testlist=sanity
Change-Id: Ide1a712858770e373404445b06596130a574d85b
Reviewed-on: https://review.whamcloud.com/28593
Tested-by: Jenkins
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>