Correctly upgrade all apt related packages

/cc @jm @rafael 

/reviewed-on nexedi/slapos.package!83

playbook/roles/upgrade-apt/tasks/main.yml

+
+- name: Install dctrl-tools using apt
+  apt: name=dctrl-tools state=latest
+
+- name: get packages to upgrade
+  shell: grep-status -X -S apt -ns Package
+  register: packages_to_upgrade
+  check_mode: no
+
+- name: Upgrade all apt related packages
+  apt: name={{ packages_to_upgrade.stdout.split('\n') }} state=latest

playbook/roles/vifib-upgrade/meta/main.yml

@@ -12,7 +12,7 @@ dependencies:
   - { role: package, package_name: exim4-base, package_state: absent }
   - { role: package, package_name: slapos-node, package_state: latest }
   - { role: package, package_name: re6st-node, package_state: latest }
-  - { role: package, package_name: apt, package_state: latest }
+  - { role: upgrade-apt, when: is_debian_or_ubuntu }
   - { role: re6stnet-ensure-running }
   - { role: etckeeper }
   - { role: vifib-team-ssh-key }