Small bugs when installing on fresh Ubuntu 16.04 server about son-install

[arocha7]

Hi Manuel, both issues are now fixed as below:

• group:
  name: docker
  state: present

• file:
  path: /etc/ansible/group_vars
  state: directory
  mode: 0755

Another recurrent issue:

• sometimes, when the retrieve of the Container images spends to much time, the playbook stops

As a simple workaround,

• just retry the playbook run, ie:

ubuntu@u16:~/son-install$ ansible-playbook son-cmud.yml -e "target=localhost operation=install service=all" --limit @/home/ubuntu/son-install/son-cmud.retry

Nice to hear from you, Alberto