Add a better error message for service

While migrating my playbook to a newer ansible version, I faced
the error message "unknown init system, cannot enable service". It turned
out to be caused by a wrong service name that was not expanded anymore.

So by giving the name of the service that cannot be enabled and a more precise
reason, i think people will be able to diagnose their issue more easily.

Fixes #6737

should now work with versions older than 8.4

Update facts.py

Fixes #7093 --devel

Add an example to show all hostvars using debug

Small bug - 'acts' should be 'facts'

Prevent catching unrelated exceptions

Add check of return code for autoinstallation of python-apt

Fixes #7084

Improve error message when multiple action are given

fixed issue with FreeBSD network facts

Clean a bit more the ssh_args configuration

Enhance error message about missing ControlPersist

fixed ETIME issue on FreeBSD 8 through 10, which broke fact gather

This will allow easier debugging through more meaningful error message.

This is a useful example to help debug how facts and vars are being collated.

This can be illustrated using this playbook:

    - command: id
      delegate_to: "{{ remote_server }}"
      user: "{{ remote_user }}"

The error is to use 'user' instead of 'remote_user', but the error message
do not really mention it, so it can be a bit hard to spot.

versions and it now works

gathering

If someone add ssh_args = " " to his .ansible.cfg, it will result into
strange failure later :

    <server.example.org> ESTABLISH CONNECTION FOR USER: misc
    <server.example.org> REMOTE_MODULE ping
    <server.example.org> EXEC ['ssh', '-C', '-tt', '-q', ' ', '-o', 'KbdInteractiveAuthentication=no',
    '-o', 'PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey', '-o', 'PasswordAuthentication=no',
    '-o', 'ConnectTimeout=10', 'server.example.org', "/bin/sh -c 'mkdir -p /tmp/ansible-tmp-1397947711.21-5932460998838
    && chmod a+rx /tmp/ansible-tmp-1397947711.21-5932460998838 && echo /tmp/ansible-tmp-1397947711.21-5932460998838'"]
    server.example.org | FAILED => SSH encountered an unknown error during the connection. We recommend you re-run the
    command using -vvvv, which will enable SSH debugging output to help diagnose the issue

The root cause is the empty string between -q and -o, who kinda break mkdir.

ansible_ssh_args is good for playbook, but in the ~/.ansible.cfg
file, it should be ssh_args in a specific section.

Fixes #7006

Fixes #7009

hint to install python-ssl on redhat systems

docker.client.APIError has moved to docker.errors.APIError

see https://github.com/dotcloud/docker-py/commit/18d4db09ecc79cef49830fa2c28c5e99dd02be42

Fixes #7024

skipped callback in loop does not display 'item'.