Absolute URI for a RestRequest only keeps the path and query

[fubar-coder]

The following test case fails:

using (var client = new RestSharp.Portable.WebRequest.RestClient("https://www.itsg-trust.de/ostc/")
{
    HttpClientFactory = CreateClientFactory(typeof(WebRequestHttpClientFactory), false),
})
{
    var request = new RestRequest(new Uri("http://www.itsg.de/tc_keys_arbeitgeberverfahren.ITSG"));
    var targetUri = client.BuildUri(request);
    Assert.Equal(new Uri("http://www.itsg.de/tc_keys_arbeitgeberverfahren.ITSG"), targetUri);
}