`HostingServiceHTTPRequest.open()` built a `CertificateVerificationHTTPSHandler` without telling it which server the request was for. The handler's `hostname` and `port` arguments therefore had no callers, and the handler was left without an SSL context until `https_open()` built one from the request URL. These are now passed in from the request's URL, so the context is available as soon as the handler is constructed. Testing Done: - `BuildSSLContextFromSSLCertTests.test_open_with_https` failed before this change, asserting against a `None` context. It now passes. - Ran unit tests for `reviewboard.certs` and `reviewboard.hostingsvcs`.