ubuntu-unity-desktop debian not installed in automatic upgrade test

log snippet here:

```
auto-upgrade [10:00:57]: Running test: /tmp/autopkgtest.DVT7Ig/upgrade-artifacts/upgrade_run_config/pre_scripts/check-ubuntu-unity-desktop -- Results: /tmp/autopkgtest.DVT7Ig/upgrade-artifacts/upgrade_run/pre_check-ubuntu-unity-desktop/
auto-upgrade [10:00:57]: ERROR: ERROR: Something went during the prerun scripts.
cp: cannot stat '/var/log/dist-upgrade': No such file or directory
auto-upgrade [10:00:57]: Collecting system details.
auto-upgrade [10:00:57]: Cleaning up configuration files.
autopkgtest: DBG: testbed command exited with code 1
autopkgtest [10:00:58]: test upgrade: -----------------------]
autopkgtest: DBG: testbed executing test finished with exit status 1
```

This isn't necessarily an issue with unity itself but perhaps our testing, but I'm reporting it against unity as it affects the flavor. I'm attaching a zip in the comments.