Fix for 13793 postgres

Fixes #13793

1. Extends [postgres_user.present](http://docs.saltstack.com/en/latest/ref/states/all/salt.states.postgres_user.html#salt.states.postgres_user.present) and [postgres_group.present](http://docs.saltstack.com/en/latest/ref/states/all/salt.states.postgres_group.html#salt.states.postgres_group.present) with `refresh_password` attribute
2. skips `SUPERUSER` and `NOSUPERUSER` on user/group updates if no changes are to be expected (otherwise it fails with `must be a superuser to alter super..`)

@basepi Please take a look.

Hi Mathieu,

I didn't changed anything from the perspective which columns/views are
selected.

The change is supposed to skip plaintext password columns if not requested
by func arguments.

Only superuser account is able to access those and some environments e.g.
Amazon RDS for PostgreSQL forbid that.

Hopefully it makes any sense.
On Jul 5, 2014 11:23 AM, "Mathieu Le Marec - Pasquet" <
notifications@github.com> wrote:

> In salt/modules/postgres.py:
>
> >          'FROM pg_roles '
> > -        'LEFT JOIN pg_authid ON pg_roles.oid = pg_authid.oid '
>
> I remember have added support for extra tables for roles defintion because
> in pgsql < 9, views were not populated the same manner.
> Dont remember the details as i am quite a red fish.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/saltstack/salt/pull/13919/files#r14570088>.
>