Comment 6 for bug 1817689

That function does some interesting stuff to find out where a sysfs is mounted. It's broken because for some reason (don't know why), /proc isn't mounted inside the chroot when we run adduser.

AFAICT user-setup is wrong here though - it calls adduser which calls into ecryptfs. It ensures /sys is mounted but not /proc.

I don't know what was making this work before. I'm proposing to fix this directly and not track that down since it seems fairly clear that user-setup is buggy in this respect anyway.