Exit the teardown section later in rename on FreeBSD

We have to hold the teardown lock while dereferencing zfsvfs->z_os and,
I believe, when committing to the ZIL.

Note that jumping to the "out" label, "error" is always non-zero.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes #12704