[OpenAFS] openafs panic after chroot

[Jim Rees]

Seems odd to me that your reclaim vnode op does nothing.

The NetBSD code from which Darwin was derived had a bug in it that I just
fixed in the OpenBSD version.  I don't know enough about Darwin to say
whether this is a problem for you.

Originally, when a vcache was pulled off the free list in NewVCache, it got
flushed (FlushVCache) but not cleaned.  This was causing obscure refcount
screwups that only showed up when the system was busy and vnodes were in
short supply.

I changed NewVCache so it calls vgone instead of FlushVcache.  In OpenBSD
there are two paths to cleanliness, one through vgone() and the other
through NewVCache.