Change root group references to use GID 0

[xenophonf]

Summary of Changes

• On BSD the group with GID 0 is named wheel.

• Rather than change the group name on a per-operating system basis, it's simpler to reference the group by GID.
• Only change SLS files that apply to both Linux and FreeBSD.
  Testing
• Tested manually on FreeBSD

[ze42]

... has it been tested and working?

In old version (up to at least 2017.7.4), user: 0 or gid: 0 would not get any change.

if x['user']: -- implicitly converted to bool, and 0 means false...

[aboe76]

isn't it better to have this variable set via map.jinja as a string
something like 'tls_user' and 'tls_group' ?

[alxwr]

I agree with @aboe76 . Using a variable is always better than hardcoding stuff.
group: 0 would just replace a (failed) assumption with another one. (It may be correct that root's group has GID 0 on all *nix systems, but we can't know if we cover all use cases.)

[ze42]

Yeah, two options I'd see working:

• have the group in a map, with root being the default value, and BSD defining it to wheel
• get salt to fix its code

Guess the second is not easy, so a map would work fine.

[xenophonf]

I wasn't aware of that bug in Salt. A map is better. Let me see if I can fix the pull request. If not, I'll resubmit it. Thanks for the feedback!

[noelmcloughlin]

Included in #283