social v2: login model shows authorizeUri when it shouldn't

[dogeared]

If the webConfig has status DISABLED and has /login status ENABLED, the login model will still show an authorizeUri for defined providers with a null domain name.

authorizeUri should not be shown if webConfig is DISABLED, regardless of other endpoint settings within webConfig.

Steps to reproduce:

1. Disable webconfig, but enable /login

2. Make sure at least one social provider is configured for the application

3. Fire up a sample app connected to the Application, such as the Spring Boot WebMVC example.

4. http http://localhost:8080/login

You'll see output like:

{
    "accountStores": [
        {
            "authorizeUri": "https://null/authorize?response_type=stormpath_token&account_store_href=https%3A%2F%2Fapi.stormpath.com%2Fv1%2Fdirectories%2F12OvcZl9yQuldBGw7X0LZs",
            "href": "https://api.stormpath.com/v1/directories/12OvcZl9yQuldBGw7X0LZs",
            "name": "Demo-Facebook",
            "provider": {
                "clientId": "794907687304823",
                "href": "https://api.stormpath.com/v1/directories/12OvcZl9yQuldBGw7X0LZs/provider",
                "providerId": "facebook",
                "scope": "public_profile email"
            }
        },
        ...
    ],
    "form": {
        "fields": [
            {
                "label": "Username or Email",
                "name": "login",
                "placeholder": "Username or Email",
                "required": true,
                "type": "text"
            },
            {
                "label": "Password",
                "name": "password",
                "placeholder": "Password",
                "required": true,
                "type": "password"
            }
        ]
    }
}

(Notice the null in the authorizeUri. Under these conditions, the authorizeUri should not be there at all)