Comment 95 for bug 1522675

Different issue, Martin, I only fixed the update-notifier task so far.

[Impact]
Cosmetic. Warnings when installing packages using update-notifier downloading stuff

[Test case]

Install flashplugin-installer with apt and check that the output does not contain a message like this:

W: Can't drop privileges for downloading as file '...' couldn't be accessed by user '_apt'

[Regression Potential]

It just chowns /var/lib/update-notifier/package-data-downloads/partial/ to _apt:root, there should not be any regression.