Prevents module from failing with "_mysql_exceptions.Warning: Sending passwords in plain text without SSL/TLS is extremely insecure." When not using SSL/TLS.
Merge pull request #8953 from jsmartin/mysql_fix

Prevents mysql_replication from failing with "_mysql_exceptions.Warning: Sending pa...
Add documentation about bin_ansible_callbacks setting.  Standardization and cleanup.
Add version_added info.
Modules are almost always written now by mutliple authors, so don't show this field on website, since it grows obsolete and does not take into account all contributors.
Contributors are still listed on github module source and in repo, and original authors still in the file for when development questions arise, but want
to funnel support questions to the mailing list versus directly to them.
Fix typo in redis cache change from 10afaee1
LinuxService: check properly if systemd is running

Use a pure Python reimplementation of the [sd_booted(3)][1] function
from [systemd v210][2].

[1]: http://www.freedesktop.org/software/systemd/man/sd_booted.html
[2]: http://cgit.freedesktop.org/systemd/systemd-stable/tree/src/libsystemd/sd-daemon/sd-daemon.c?id=v210#n465
Transform comment into docstring
LinuxService: use the same logic as systemd for appending .service to an unit

There's no need for complex rules to determine if `.service` should be
appended to a unit's name, just do like systemd does.  For more details
see commit [696c245a23d55e4249651573eb9c61b68e61580c][1] and
[`unit_name_mangle`][2] from systemd.

[1]: http://cgit.freedesktop.org/systemd/systemd/commit/?id=696c245a23d55e4249651573eb9c61b68e61580c
[2]: http://cgit.freedesktop.org/systemd/systemd/tree/src/shared/unit-name.c?id=696c245a23d55e4249651573eb9c61b68e61580c#n501
LinuxService: check properly if systemd manages the unit

There's no need to list and look at all the unit files, just check the
[load state][1] of the current unit by running `systemctl -p LoadUnit show`.

This also covers cases like when an unit is masked (which means that
systemd can't start or enable it).

[1]: http://cgit.freedesktop.org/systemd/systemd-stable/tree/src/shared/unit-name.c?h=v208-stable#n52
LinuxService.get_service_tools: check for systemd first

Check for systemd first then for legacy init systems. This simplifies
the code.
LinuxService: d.get(k, None) -> d.get(k)

From the documentation:
> D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.

So there's no need for the `None` parameter.