cherry-pick a few patches from zfs-2.1.7-staging

cherry-pick a few patches from zfs-2.1.7-staging

While checking the current state of 2.1.6 we noticed that there were
some changes in debian-upstream [0] resulting from a bug-report in
zfs-upstream [1].

Our packages should be unaffected (they do not ship the
init-scripts in the first place).
Since the issue was fixed by zfs-upstream already on the
zfs-2.1.7-staging branch we should include it as well as it might save
users, who somehow got debian-upstream's zfs-packages installed on PVE
some trouble.

The other 2 changes seem small and isolated enough so including them
as well.

[0] https://salsa.debian.org/zfsonlinux-team/zfs/-/commits/master
[1] https://github.com/openzfs/zfs/issues/14010

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>