Support HTTPS proxies in libphutil
Summary:
When we connect via an HTTPS proxy (see detailed instructions in T1747), we get a response like this:
HTTP/1.0 200 Connection established HTTP/1.1 200 OK Normal-Http-Headers: values More-Normal-Heders: blah <html>actual response body</html>
Add code to drop these blocks when parsing responses, similar to how we drop "HTTP/1.0 100 Continue" header blocks already.
Test Plan: Followed instructions in T1747 and got normal operation with connections logged in Charles rather than unmitigated failure.
Reviewers: dreiss, vrana, btrahan
Reviewed By: dreiss
CC: aran
Maniphest Tasks: T1747
Differential Revision: https://secure.phabricator.com/D3417