upgrade tests for xenial

[landam]

Currently roles system/test.yml are disabled and need to be updated for xenial.

[landam]

Open issues:

- name: Test 'gis.lab' DNS records are resolved
  shell: ping -c 1 {{ item }}.gis.lab
  with_items:
    - server
# TBF:
#    - boot
#    - web

and

# TBF: not working
- name: Test if email to root user was forwarded to test superuser
  shell: >
    sleep 2
    &&
    grep -r "This is a test message sent by GIS.lab test {{ GISLAB_TEST_UNIQUE_STRING }}"
    /mnt/home/test_mail_{{ GISLAB_TEST_UNIQUE_STRING }}/Mail/new