The repo is not needed any more, because the Google Cloud SDK is not
installed in the images by default. If anyone wants to install the SDK,
they can add the appropriate repo definition.
The Google SDK ships pre-compiled binaries. It is undesirable to install
it by default in `gce` and `gce-rhui` in its current shape. Also not
installing it does not anyhow affect the RHEL integration as the guest
OS in GCP.