Force install packages on test on MR

When running test on MR it can happen that some packages are held back and cannot be easily upgraded with apt-get update. To overcome this situation, force the upgrade using apt-get full-upgrade.

A common example of this situation is testing the linux kernel which can produce warnings like:

Install packages | The following packages have been kept back: Install packages | linux-headers-amd64

Signed-off-by: Walter Lozano walter.lozano@collabora.com