FreeBSD needs a wrapper for handling zfs_cmd ioctls.
In libzfs this is handled by zfs_ioctl. However, here
we need to wrap the call directly.
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9511
