Comment 6 for bug 891045

This may get fixed by the fix to bug 997978.

However I'm hesitant to mark this a dup of that, since the more generic problem of upgrading in a chroot will have cases where the chroot is in a shape where we cannot do the right thing.

But I'm going to mark it as such anyway, because while there are cases where we can't guess what to do with /dev/shm, the fix should stop the warning, which I guess is the real bug here.