certctl: Set METALOG ownership to root:wheel

This sets the correct ownership values when building base.txz

install(1) does not validate the arguments passed to -o or -g
(see PR283355) so there's no need to have the passwd db available
for now. Future work includes plumbing the appropriate passwd db
path through certctl, and validating uid and gid in install(1).

PR: 283340
Reviewed by: jrtc27
Differential Revision: https://reviews.freebsd.org/D48506

(cherry picked from commit 10fa3f2518d4582c98d74527f79af9f30b1eceab)
(cherry picked from commit 98bebc20cef7527ccb15f8defc9d52e803a0d506)
(cherry picked from commit 4d15b58365ea706129bedfdb37e0c5e8661a640f)