Enhance error message about missing ControlPersist

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

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.
ifconfig changed on FreeBSD, tested this on 8,9 and 10 latest stable
versions and it now works
Improve error message when multiple action are given

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.
Add an example to show all hostvars using debug

This is a useful example to help debug how facts and vars are being collated.
Explicit check of return code for autoinstallation of python-apt added

This will allow easier debugging through more meaningful error message.
Prevention for catching unrelated exceptions added
Small bug - 'acts' should be 'facts'
Merge pull request #7078 from mscherer/fix_error_message_controlpersist

Enhance error message about missing ControlPersist
Merge pull request #7079 from mscherer/fix_error_whitespace_in_config

Clean a bit more the ssh_args configuration
Merge pull request #7082 from bcoca/freebsd_mtu_fix

fixed issue with FreeBSD network facts
Merge pull request #7083 from mscherer/better_message_multiple_action

Improve error message when multiple action are given
Properly catch and decode unicode strings in module _log_invocation()

Fixes #7084
Merge pull request #7094 from radeksimko/apt-autoinstall-fix

Add check of return code for autoinstallation of python-apt
Merge pull request #7095 from radeksimko/pokemon-exc-fix

Prevent catching unrelated exceptions
Merge pull request #7096 from CaptTofu/docker

Small bug - 'acts' should be 'facts'
Merge pull request #7089 from dagwieers/debug-docs

Add an example to show all hostvars using debug
Update facts.py

Fixes #7093 --devel
Merge pull request #7099 from faust64/patch-2

Update facts.py
should now work with versions older than 8.4