Add a test targeting bugzilla bug #1114640

To test [BZ 1114640](https://bugzilla.redhat.com/show_bug.cgi?id=1114640), write a test that creates a parameter for the operating
system with ID 1. As part of this effort, create entity `OperatingSystemParameter`
and partially test it.
You could do something like that. For example:

```python
osp = entities.OperatingSystemParameter(
    operating_system_id=1,
    id=osp_attrs['id']
).read()
```

I've chosen not do do that because the API design makes that really, really hard to do. You know how the API can often accept parameters via either the URL or as a JSON argument? In this case, you really have to use URL arguments, even though I prefer to use JSON arguments. For example, these calls fail:

    HTTP GET api/v2/operatingsystems/parameters/:id
    HTTP GET api/v2/parameters/:id

...where an OS ID is provided as a JSON argument. Also, when this request completes:

    HTTP GET api/v2/operatingsystems/:id/parameters/:id

...the server does not provide an OS ID. So you have to override `OperatingSystemParameter.read` to deal with the fact that no OS ID is returned. Also, providing an OS ID as a JSON parameter is positively *dangerous* in all of these cases:

    HTTP GET api/v2/operatingsystems/:id/paramters/:id
    HTTP PUT api/v2/operatingsystems/:id/paramters/:id
    HTTP DELETE api/v2/operatingsystems/:id/paramters/:id

Undefined behaviour will result if you provide an OS ID as JSON in the above calls.

So... does that make sense?