Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1449749

Description of problem:
On Sat 6.2 and earlier POST /api/v2/hosts sends `host_parameters_attributes` as data and returns all the attributes for created host, including `parameters`. Now it does not return this field at all and additional GET request is needed to obtain `parameters`.

Example using nailgun tool:

1. Send POST request with defined `host_parameters_attributes`
   In [9]: host = entities.Host(server_config, host_parameters_attributes=[{'name': 'abc', 'value': 'xyz'}]).create_json(create_missing=True)

1. Check that `parameters is missing in response
   In [10]: 'parameters' in host
   Out¹⁰: False

1. Send GET request and check that parameters was returned
   In [11]: 'parameters' in entities.Host(server_config, id=host['id']).read_json()
   Out¹¹: True

In [12]: entities.Host(server_config, id=host['id']).read_json()['parameters']
Out¹²:
[{u'created_at': u'2017-05-10 14:48:02 UTC',
u'id': 9,
u'name': u'abc',
u'priority': 70,
u'updated_at': u'2017-05-10 14:48:02 UTC',
u'value': u'xyz'}]

Version-Release number of selected component (if applicable):
Satellite Downstream nightly / 6.3:

• satellite-6.3.0-11.1.beta.el7sat.noarch
• foreman-1.15.0-0.develop.201703271956git40dd32b.el7sat.noarch

How reproducible:
Always

Steps to Reproduce:
1. Create a host by issuing a POST request to /api/v2/hosts
2. Check its response
3.

Actual results:
`parameters` is missing

Expected results:
`parameters` should be returned

Additional info: