zsys-commit.service will fail when zfs tools don't match DKMS version

[Some Guy On The Net]

Originally reported the bug in [zsys's github issues](https://github.com/ubuntu/zsys/issues/220), wanting to link to zfs-linux bug, reporting it here to link it.

**Describe the bug**
This isn't a bug in `zsys` so much as a bug in the way Ubuntu manages ZFS packages which `zsys` relies on.

The root cause is already reported at:
> https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1939210

When using HWE based kernel, the zfs-kmod is updated (currently to 2.x) while the LTS zfs packages are at 0.8.3
Currently the solution is to update the tools, the bug linked above points to a 3rd party ppa with updated tools.

The reason for reporting the bug here
- it affects the `zfs promote` command, which is used after a restore from a previous state occurs. So I thought this would be a good place to document this issue.
- I also suggest that `zsysctl` should test for this discrepancy and warn about it.
- Hoping an Ubuntu insider would help addressing this issue with the original bug maintainers for next LTS version (coming up in a couple of months)

**To Reproduce**
Steps to reproduce the behavior:
1. Make sure your system uses HWE kernel
2. Run `zfs version` and get a discrepancy in versions:
> ```
> zfs-0.8.3-1ubuntu12.13
> zfs-kmod-2.0.6-1ubuntu2
> ```
2. Make sure you have a saved zsys state in your GRUB menu.
3. Reboot to GRUB and select a saved state
4. Run `systemctl status zsys-commit` to see the error.
    `zsys-commit` service runs the equivalent of `sudo zsysctl boot commit` which marks the boot as successful.

> ```
> ● zsys-commit.service - Mark current ZSYS boot as successful
> Loaded: loaded (/lib/systemd/system/zsys-commit.service; enabled; vendor preset: enabled)
> Active: failed (Result: exit-code) since Sun 2022-01-23 23:21:41 EST; 10h ago
> Main PID: 12287 (code=exited, status=1/FAILURE)
>
> Jan 23 23:21:40 hostname systemd[1]: Starting Mark current ZSYS boot as successful...
> Jan 23 23:21:41 hostname zsysctl[12287]: level=error msg="couldn't commit: couldn't promote dataset \"rpool/ROOT/ubuntu_ssfirw\": couldn't promote \"rpool/ROOT/ubuntu_ssfirw\": not a cloned filesystem"
> Jan 23 23:21:41 hostname systemd[1]: zsys-commit.service: Main process exited, code=exited, status=1/FAILURE
> Jan 23 23:21:41 hostname systemd[1]: zsys-commit.service: Failed with result 'exit-code'.
> Jan 23 23:21:41 hostname systemd[1]: Failed to start Mark current ZSYS boot as successful.
> ```

**Expected behavior**
> ```
> ● zsys-commit.service - Mark current ZSYS boot as successful
> Loaded: loaded (/lib/systemd/system/zsys-commit.service; enabled; vendor preset: enabled)
> Active: active (exited) since Mon 2022-01-24 18:51:11 EST; 15h ago
> Main PID: 297120 (code=exited, status=0/SUCCESS)
> Tasks: 0 (limit: 18951)
> Memory: 0B
> CGroup: /system.slice/zsys-commit.service
>
> Jan 24 18:51:10 Sygin systemd[1]: Starting Mark current ZSYS boot as successful...
> Jan 24 18:51:11 Sygin systemd[1]: Finished Mark current ZSYS boot as successful.
> ```

**ubuntu-bug output**
I'm no longer in the broken state, and didn't run `ubuntu-bug` before.
Bug report (mentioned above) contains much more info.

**Installed versions:**
- OS: Zorin OS 16 (based on Focal Fossa - Ubuntu 20.04 LTS)
- Zsysd running version: 0.4.8

**Additional context**
I've documented my ordeal as an askubuntu question which I ended up answering ([link](https://askubuntu.com/a/1389086/720005)).

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.