Golang Http Clients Do Not Respect User Options

As of 72ca60d, the instantiation of an http client with user-supplied options (NewTHttpClientWithOptions) disregards options.

The target endpoint is tested with the following snippet:

response, err := http.Get(urlstr)

However, a user-supplied THttpClientOptions contains a client that should be used to test the endpoint instead, i.e.,

response, err := options.Client.Get(urlstr)

The user-supplied client may have settings that are required to communicate with the target endpoint.

Though this fix seems simple, I have not supplied a patch, as this fix should likely be bundled with a greater overarching patch to THRIFT-4215. That is because the single line change above may not include all the fixes necessary to propagate client options correctly through the construction of a THttpTransport, and further errors are squelched.