svn commit: r341665 - in head: sys/geom/mirror tests/sys/geom/class/mirror

[Conrad Meyer]

This minor part was removed from the revision during review, but I
forgot to remove it from the commit message.  Sorry about the mistake,
and please disregard:

On Thu, Dec 6, 2018 at 3:55 PM Conrad Meyer <cem at freebsd.org> wrote:
>   When we are instructed to forget mirror components, bump the generation id
>   to avoid confusion with such stale components later.

Thanks,
Conrad