Now we have the following ways to set additional arguments:

1. [ssh_connection]ssh_args in ansible.cfg: global setting, prepended to
   every command line for ssh/scp/sftp. Overrides default ControlPersist
   settings.
2. ansible_ssh_common_args inventory variable. Appended to every command
   line for ssh/scp/sftp. Used in addition to ssh_args, if set above, or
   the default settings.
3. ansible_{sftp,scp,ssh}_extra_args inventory variables. Appended to
   every command line for the relevant binary only. Used in addition to
   #1 and #2, if set above, or the default settings.
3. Using the --ssh-common-args or --{sftp,scp,ssh}-extra-args command
   line options (which are overriden by #2 and #3 above).

This preserves backwards compatibility (for ssh_args in ansible.cfg),
but also permits global settings (e.g. ProxyCommand via _common_args) or
ssh-specific options (e.g. -R via ssh_extra_args).

Fixes #12576

commit 9921bb9d2002e136c030ff337c14f8b7eab0fc72
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Mon Aug 10 20:19:44 2015 +0530

    Document --ssh-extra-args command-line option

commit 8b25595e7b1cc3658803d0821fbf498c18ee608a
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Thu Aug 13 13:24:57 2015 +0530

    Don't disable GSSAPI/Pubkey authentication when using --ask-pass

    This commit is based on a bug report and PR by kolbyjack (#6846) which
    was subsequently closed and rebased as #11690. The original problem was:

        «The password on the delegated host is different from the one I
        provided on the command line, so it had to use the pubkey, and the
        main host doesn't have a pubkey on it yet, so it had to use the
        password.»

    (This commit is revised and included here because #11690 would conflict
    with the changes in #11908 otherwise.)

    Closes #11690

commit 119d0323892c65e8169ae57e42bbe8e3517551a3
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Thu Aug 13 11:16:42 2015 +0530

    Be more explicit about why SSH arguments are added

    This adds vvvvv log messages that spell out in detail where each SSH
    command-line argument is obtained from.

    Unfortunately, we can't be sure if, say, self._play_context.remote_user
    is obtained from ANSIBLE_REMOTE_USER in the environment, remote_user in
    ansible.cfg, -u on the command line, or an ansible_ssh_user setting in
    the inventory or on a task or play. In some cases, e.g. timeout, we
    can't even be sure if it was set by the user or just a default.

    Nevertheless, on the theory that at five v's you can use all the hints
    available, I've mentioned the possible sources in the log messages.

    Note that this caveat applies only to the arguments that ssh.py adds by
    itself. In the case of ssh_args and ssh_extra_args, we know where they
    are from, and say so, though we can't say WHERE in the inventory they
    may be set (e.g. in host_vars or group_vars etc.).

commit b605c285baf505f75f0b7d73cb76b00d4723d02e
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Tue Aug 11 15:19:43 2015 +0530

    Add a FAQ entry about ansible_ssh_extra_args

commit 49f8edd035cd28dd1cf8945f44ec3d55212910bd
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Mon Aug 10 20:48:50 2015 +0530

    Allow ansible_ssh_args to be set as an inventory variable

    Before this change, ssh_args could be set only in the [ssh_connection]
    section of ansible.cfg, and was applied to all hosts. Now it's possible
    to set ansible_ssh_args as an inventory variable (directly, or through
    group_vars or host_vars) to selectively override the global setting.

    Note that the default ControlPath settings are applied only if ssh_args
    is not set, and this is true of ansible_ssh_args as well. So if you want
    to override ssh_args but continue to set ControlPath, you'll need to
    repeat the appropriate options when setting ansible_ssh_args.

    (If you only need to add options to the default ssh_args, you may be
    able to use the ansible_ssh_extra_args inventory variable instead.)

commit 37c1a5b6794cee29a7809ad056a86365a2c0f886
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Mon Aug 10 19:42:30 2015 +0530

    Allow overriding ansible_ssh_extra_args on the command-line

    This patch makes it possible to do:

        ansible somehost -m setup \
            --ssh-extra-args '-o ProxyCommand="ssh -W %h:%p -q user@bouncer.example.com"'

    This overrides the inventory setting, if any, of ansible_ssh_extra_args.

    Based on a patch originally by @Richard2ndQuadrant.

commit b023ace8a8a7ce6800e29129a27ebe8bf6bd38e0
Author: Abhijit Menon-Sen <ams@2ndQuadrant.com>
Date:   Mon Aug 10 19:06:19 2015 +0530

    Add an ansible_ssh_extra_args inventory variable

    This can be used to configure a per-host or per-group ProxyCommand to
    connect to hosts through a jumphost, e.g.:

        inventory:
            [gatewayed]
            foo ansible_ssh_host=192.0.2.1

        group_vars/gatewayed.yml:
            ansible_ssh_extra_args: '-o ProxyCommand="ssh -W %h:%p -q bounceuser@gateway.example.com"'

    Note that this variable is used in addition to any ssh_args configured
    in the [ssh_connection] section of ansible.cfg (so you don't need to
    repeat the ControlPath settings in ansible_ssh_extra_args).

The --new-vault-password-file option works the same as
--vault-password-file but applies only to rekeying (when
--vault-password-file sets the old password). Also update the manpage
to document these options more fully.

Support for ANSIBLE_HOSTS is faded out, see commit
c7325454, therefore do not mention it in
the man pages.

Fixes #9574

Fixes #9758

Note: the man page needs to be rebuilt.

Fixes #6471

Partially resolves #6471

raise errors when omitted, updated changelog with new modules.

Same doc-typo (confirmed) as https://github.com/ansible/ansible/pull/4759

--remote-user  *should be*  --user

--remote-user= does not work:
 ansible: error: no such option: --remote-user

--user= does. Updating docs

Thi permit to simplify the command line to use by using
a sensible default, and so reduce the number of incorrect
possible choices and setup needed. Among potential
incorrect choices is using a fixed directory in /tmp, which
could be problematic with a setup whose access is not
properly restricted.