ubuntu-desktop should not hard depend on update-notifier (make it a recommended dep instead)

[vvhk]

The package `ubuntu-desktop` hard depends on `update-notifier` which is not good. It would be much better if it were a recommended dependency.

Namely, the problem I initially wanted to report was with `update-notifier` not being configurable enough so it shows itself when you run apt manually on the command line. Pretty sure there's plenty of legitimate scenarios where desktops would be managed from command line. Think fleets of desktops in an office managed with SaltStack. Think scheduling updates to specific periods of time, outside of which you do not want to be nagged, even on single computers. And disabling updates from the Ubuntu Software app does not prevent the nagging when you operate `apt` manually. Neither does dconf-editor's com.ubuntu.update-notifier.no-show-notifications.

Anyway, removing `update-notifier` solved the problem and then I realized that indeed, on machines where you do not want GUI for updates, you simply remove the package.

And so this report is made. Please make it a recommended, not a hard dep of the desktop.

[vvhk (vvhk-deactivatedaccount-deactivatedaccount)]

See also bug #1210138.

[Launchpad Janitor (janitor)]

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

[Steve Langasek (vorlon)]

update-notifier is part of the designed experience of the Ubuntu Desktop and it should not be necessary to remove it to address the issues you've identified. Reassigning to update-notifier.