kern/145818: [geom] geom_stat_open showing cached information for non-present iso

[Garrett Cooper]

    I did some more tracking down of this issue and the problem is
with the cached data being reported by devstat(9) -- somehow when the
device is being detached it's not properly reporting that it needs to
be removed in geom(4). I'm a bit stuck after that, but it does appear
to be a communication issue between [atapi]cam(4) and geom(4).
Thanks,
-Garrett