LU-11024 osd-zfs: properly detect ZFS dnode accounting

LU-11024 osd-zfs: properly detect ZFS dnode accounting

Properly detect if native ZFS dnode accounting is available for
ZFS 0.7.x releases that do not contain ZFS project quota.  The
function signature changed after ZFS Project Quota was landed,
but we still need to check for the old function for 0.7.x.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Icd40e0bdaa0b7738e9aa761836167780843ebbe5
Reviewed-on: https://review.whamcloud.com/32422
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>