Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1436123

Description of problem:
API/Hammer show different results then Webui

Version-Release number of selected component (if applicable):
Satellite 6.2.8

How reproducible:
100%

Steps to Reproduce:
1) Create a new hostgroup without specifying architecture or OS:

1. hammer hostgroup create --name "AXE" --organizations "Default Organization"

2) Check it via API:

1. curl -X GET -s -k -u user:pass "https://localhost:443/api/v2/hostgroups/" | python -mjson.tool
   ~~~ {
   "page": 1,
   "per_page": 200,
   "results": [ {
   "ancestry": null,
   "architecture_id": null,
   "architecture_name": null,
   "compute_profile_id": null,
   "compute_profile_name": null,
   "created_at": "2017-03-27 07:28:51 UTC",
   "domain_id": null,
   "domain_name": null,
   "environment_id": null,
   "environment_name": null,
   "id": 1,
   "medium_id": null,
   "medium_name": null,
   "name": "AXE",
   "operatingsystem_id": null,
   "operatingsystem_name": null,
   "parent_id": null,
   "parent_name": null,
   "ptable_id": null,
   "ptable_name": null,
   "puppet_ca_proxy_id": null,
   "puppet_proxy_id": null,
   "realm_id": null,
   "realm_name": null,
   "subnet_id": null,
   "subnet_name": null,
   "title": "AXE",
   "updated_at": "2017-03-27 07:28:51 UTC"
   }
   ],
   "search": null,
   "sort": {
   "by": null,
   "order": null
   },
   "subtotal": 1,
   "total": 1
   }
   ~~~

Specify an arch / OS / Media / partition via webui and save it, this is the output from API:

1. curl -X GET -s -k -u user:pass "https://localhost:443/api/v2/hostgroups/" | python -mjson.tool
   ~~~ {
   "page": 1,
   "per_page": 200,
   "results": [ {
   "ancestry": null,
   "architecture_id": 1,
   "architecture_name": "x86_64",
   "compute_profile_id": null,
   "compute_profile_name": null,
   "created_at": "2017-03-27 07:43:16 UTC",
   "domain_id": null,
   "domain_name": null,
   "environment_id": null,
   "environment_name": null,
   "id": 2,
   "medium_id": 11,
   "medium_name": "pipopopo/Library/Red_Hat_Server/Red_Hat_Enterprise_Linux_7_Server_Kickstart_x86_64_7_2",
   "name": "AXE",
   "operatingsystem_id": 1,
   "operatingsystem_name": "RedHat 7.2",
   "parent_id": null,
   "parent_name": null,
   "ptable_id": 72,
   "ptable_name": "CoreOS default fake",
   "puppet_ca_proxy_id": null,
   "puppet_proxy_id": null,
   "realm_id": null,
   "realm_name": null,
   "subnet_id": null,
   "subnet_name": null,
   "title": "AXE",
   "updated_at": "2017-03-27 07:45:05 UTC"
   }
   ],
   "search": null,
   "sort": {
   "by": null,
   "order": null
   },
   "subtotal": 1,
   "total": 1
   }
   ~~~

3) Reverting the action by removing the OS/Arch/Partition/Media via Webui

Do API call to watch the results:

1. curl -X GET -s -k -u virt-who:virt-who "https://localhost:443/api/v2/hostgroups/" | python -mjson.tool
   ~~~ {
   "page": 1,
   "per_page": 200,
   "results": [ {
   "ancestry": null,
   "architecture_id": null,
   "architecture_name": null,
   "compute_profile_id": null,
   "compute_profile_name": null,
   "created_at": "2017-03-27 07:43:16 UTC",
   "domain_id": null,
   "domain_name": null,
   "environment_id": null,
   "environment_name": null,
   "id": 2,
   "medium_id": null,
   "medium_name": null,
   "name": "AXE",
   "operatingsystem_id": 1,
   "operatingsystem_name": "RedHat 7.2",
   "parent_id": null,
   "parent_name": null,
   "ptable_id": null,
   "ptable_name": null,
   "puppet_ca_proxy_id": null,
   "puppet_proxy_id": null,
   "realm_id": null,
   "realm_name": null,
   "subnet_id": null,
   "subnet_name": null,
   "title": "AXE",
   "updated_at": "2017-03-27 08:32:04 UTC"
   }
   ],
   "search": null,
   "sort": {
   "by": null,
   "order": null
   },
   "subtotal": 1,
   "total": 1
   }
   ~~~

To confirm I checked it also via hammer:

1. hammer hostgroup info --id 2
   ~~~
   [Foreman] Password for admin:
   Id: 2
   Name: AXE
   Title: AXE
   Operating System: RedHat 7.2
   Puppet CA Proxy Id:
   Puppet Master Proxy Id:
   Puppetclasses:

Parameters:

Organizations:
pipopopo
Parent Id:
~~~

Actual results:
It seems that all the fields were reverted to null except for the Operating System.

~_{~
"operatingsystem_id": 1,
"operatingsystem_name": "RedHat 7.2",}
~~

Expected results:
everything back to null as also shown in the Webui

Additional info:
This creates a discrepancy between hammer/API and what's seen in the webui.