[BUG] mysql_query.run output=grain - Whitespace in dictionary key

Description
I'm writing a state for automate Icingaweb2 database stuff.
For checking if someone has changed the password of an account "admin" i will check the pasword_hash and must save the mysq_query.run output to the grains to be able to use the content of the grain for later checks.
My problem now is that in the dictionary of the grain is a key called "rows returned" that has a whitespace in his name. So i'm not able to call it with salt-call grains.get icingaweb2:mysql_check_user:rows returned.
But if this key would be called "rows_returned" then i can call it with salt-call grains.get icingaweb2:mysql_check_user:rows_returned.

Setup
State:

Check_user_{{ username }}_and_password:
  mysql_query.run:
    - database: icingaweb2
    - query: "Select name,password_hash FROM icingaweb_user WHERE name = 'admin' AND password_hash = '{{ user['pwdhash'] }}';"
    - output: grain
    - grain: icingaweb2
    - key: mysql_check_user

debianserver: ~/ $ salt-call grains.get icingaweb2:mysql_check_user

local:
    ----------
    columns:
        - name
        - password_hash
    query time:
        ----------
        human:
            0.2ms
        raw:
            0.00018
    results:
    rows returned:
        0

Expected behavior
debianserver: ~/ $ salt-call grains.get icingaweb2:mysql_check_user

local:
    ----------
    columns:
        - name
        - password_hash
    query time:
        ----------
        human:
            0.2ms
        raw:
            0.00018
    results:
    rows_returned:
        0

Versions Report

Start at the mysql_query.run handling for output=grain and trace how its result dictionary is exposed through salt-call grains.get. Reproduce the icingaweb2 example, then verify that the returned key uses an underscore so it can be queried as rows_returned.