Update zfs.rst
Update zfs.rst

This accounts for the change to the JSON output of a sysadm/zfs "list_pools" action.
pcbsd/sysadm,pcbsd/sysadm,c3d2/sysadm,c3d2/sysadm,pcbsd/sysadm,c3d2/sysadm,pcbsd/sysadm,c3d2/sysadm,pcbsd/sysadm