Comment 0 for bug 1905986

[Impact]

 * gce-compute-image-packages has been split to multiple source packages and google-guest-agent (written in Go) replaced the services originally written in Python. The upgrade to gce-compute-image-packages compatible with google-guest-agent replaced the Python modules (python3-google-compute-engine) with an empty transitional package. The removal of the modules could break local software relying on those modules.
 * The fix is not providing the empty python3-google-compute-engine transitional package, but adding Breaks: to google-guest-agent to force the removal of it. Since removals are not performed automatically by apt-get upgrade (not unattended-upgrades) the administrator needs to approve removal.

[Test Case]

 * Set up a system with the unfixed version of the packages, including python3-google-compute-engine installed.
 * Upgrade to the new set of packages:
   apt-get upgrade
 * Observe that the gce-compute-image-packages and python3-google-compute-engine packages are kept back.
 * Upgrade google-compute-engine manually:
   apt install google-compute-engine
 * This should succeed, removing python3-google-compute-engine

 Dist-upgrade from Trusty:
  TODO

[Where problems could occur]

 * TODO