Adds indent to _create for when no client is present

[Maxdeboer9]

Fixes: #1475

The SoapBinding Class has the possibility / the option for the client to be None.

However, when the client is None, the code fails on

            # Add extra http headers from the setings object
            if client.settings.extra_http_headers:
                http_headers.update(client.settings.extra_http_headers)

which falls outside the if client specified above. An extra indent to those lines fixes the problem.