This bug was fixed in the package unattended-upgrades - 0.96ubuntu1

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unattended-upgrades (0.96ubuntu1) artful; urgency=low

  * Merge from Debian unstable (LP: #1714019)
    - Remaining changes:
      - Recover from broken dh_installinit override in versions < 0.93.1ubuntu3
      - unattended-upgrades: Do not automatically upgrade the development
        release of Ubuntu unless Unattended-Upgrade::DevRelease is true.
    - Dropped changes, included in Debian:
      - Cherry-pick 2e5deed, f26edb4 from upstream to add support for a
        --download-only option, enabling us to download updates at a random
        time of day by default but apply them predictably in the 6am-7am
        window.
      - Fix PEP8 failures (replace except: with except Exception:)
      - unattended-upgrades: Provide some information and create a log entry
        when there is a failure to parse the allowed origins.
      - Add UbuntuESM to the list of sources automatically upgraded from by
        default.
      - Complete the solution for the unattended-upgrades.service unit not
        correctly working
      - d/rules : Remove the override_dh_installinit. The stop option is no
        longer available so the command falls back to default. This is the
        normal behavior so the override is not required
      - d/unattended-upgrades.init : Add Default-Start runlevels, otherwise
        the unattended-upgrades.service unit cannot be enabled on boot
      - d/postinst : Cleanup the stop symlinks created by the wrong
        override_dh_installinit. Without that, the systemd unit cannot be
        enabled correctly.
        Force disable the service before deb-systemd-helper runs so the old
        symlink is not left dangling (workaround for Debian Bug #797108).
        Force enable and start of the systemd unit to work around Debian Bug
        #797108 which fails to enable systemd units correctly when
        WantedBy= statement is changed which is the case here.
      - d/unattended-upgrades.service : Fix the service so it runs correctly on
        shutdown :
        - Remove DefaultDependencies=no : Breaks normal shutdown dependencies
        - Set After= to network.target and local-fs.target. Since our service
          is now ExecStop, it will run before network and local-fs become
          unavailable.
        - Add RequiresMountsFor=/var/log /var/run /var/lib /boot : Necessary if
          /var is a separate file system. Set WantedBy= to multi-user.target
      - Add DEP8 tests to verify the following :
        - Verify that the unattended-upgrades.service unit is enabled and
          started.
        - Verify that InstallOnShutdown works when configured.
      - The systemd unit needs to be an ExecStop since it is is activated on
        shutdown. Otherwise, it will get scheduled after completion of
        the local-fs.target. In the case where /var is a separate
        filesystem, unattended-upgrade-shutdown will hang until timeout
        since /var/run is expected but no longer there
      - When performing a sanity check for packages to install or upgrade
        return false when either there are no packages in the cache or the
        package to upgrade is not in the change set.
      - Do not mark packages for deletion / autoremoval if unattended-upgrades
        is being run in dry-run mode.
      - Store delay command line option as an int not a string since we do
        maths with it.

 -- Balint Reczey <email address hidden>  Wed, 30 Aug 2017 13:46:37 +0200