Install "just enough" dependencies

[Allan LeSage]

Discussing with Richard, encountering a "no space left on device" error in Jenkins while using the -i option. Richard suggesting:

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@allanlesage the no space left on device is normally only seen when using the -i option to install the dependencies onto system. - Most likely due to lots of updates in archive as you mentioned.

Removing -i option should help resolve this, but could lead to problem where some required updates don't get installed. Another option could be to mark mediaplayer-app-autopilot as # TMPINSTALL in debian/tests/control, I think this is about 11MB, then you could continue to use -i option.

I think ideally we need an option to allow only apps/unity8 updates and make sure that only they can be installed to system, whilst leaving everything else in tmp.
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Use this bug to hash out what needs to go into /tmp/ and not--is it rdepends of unity8-autopilot, e.g.? And implement this so that we never have to tinker with this setting in Jenkins at least.

[Allan LeSage (allanlesage)]

The new -p install-production-deps option leverages rhuddie's apt-cacher and installs only the necessary items into / proper, the rest into userspace, and so should fix this--merged, will monitor.

[platform-qa-bot (platform-qa-bot)]

Fix committed into lp:ubuntu-system-tests at revision None, scheduled for release in ubuntu-system-tests, milestone Unknown