Unable to assign interface to IP address via API

[explody]

Environment

• Python version: 3.6.5, 3.5.x
• NetBox version: 2.4-beta1

Steps to Reproduce

Using the API, attempt to PUT or PATCH an existing IP address including an interface id.

postman CURL output. Both IP and iface ID #'s exist and are correct
curl -X PATCH \
  https://ourhost/api/ipam/ip-addresses/11111/ \
  -H 'authorization: Token XXXX' \
  -H 'cache-control: no-cache' \
  -H 'content-type: application/json' \
  -H 'postman-token: XXXX' \
  -d '{
    "interface": 2222
}'

Expected Behavior

The IP would now be assigned to the given interface.

Observed Behavior

From postman, the following error:

{
    "interface": {
        "non_field_errors": [
            "Invalid data. Expected a dictionary, but got int."
        ]
    }
}

We additionally tried to pass interface data as a nested hash, but encountered a variety of other errors. It appears that the shown approach should work, so this may hint at the base problem.

[jeremystretch]

Fixed in #2300. Thanks @explody!