px: NTLM authentication no longer possible

Hi,

I think the latest pre-release is no longer able to authenticate against our proxy.

This is the current log:

Process-1: MainThread: 1519632465: verify_request: Client address: 127.0.0.1
Process-1: Thread_0: 1519632465: do_CONNECT: Entering
Process-1: Thread_0: 1519632465: do_transaction: Entering
Process-1: Thread_0: 1519632465: get_response: winkerberos SSPI
Process-1: Thread_0: 1519632465: do_socket: Entering
Process-1: Thread_0: 1519632465: do_socket_connect: New connection: ('proxy.rwe.com', 8080)
Process-1: Thread_0: 1519632465: do_socket: b'CONNECT github.com:443 HTTP/1.1\r\n'
Process-1: Thread_0: 1519632465: do_socket: Sending b'Host: github.com:443\r\n'
Process-1: Thread_0: 1519632465: do_socket: Sending b'User-Agent: git/2.15.0.windows.1\r\n'
Process-1: Thread_0: 1519632465: do_socket: Sending b'Proxy-Connection: Keep-Alive\r\n'
Process-1: Thread_0: 1519632465: do_socket: Sending extra b'Proxy-Authorization: Negotiate YIGeBgYrBgEFBQKggZM... and much more... olAmCpGQrZA=\r\n'
Process-1: Thread_0: 1519632465: do_socket: Reading response code
Process-1: Thread_0: 1519632466: do_socket: Response code: 407 False
Process-1: Thread_0: 1519632466: do_socket: Reading response headers
Process-1: Thread_0: 1519632466: do_socket: Received header Proxy-Authenticate = NEGOTIATE oRUwE6AD... and much more... BgjcCAgo=
Process-1: Thread_0: 1519632466: do_socket: Received header Cache-Control = no-cache
Process-1: Thread_0: 1519632466: do_socket: Received header Pragma = no-cache
Process-1: Thread_0: 1519632466: do_socket: Received header Content-Type = text/html; charset=utf-8
Process-1: Thread_0: 1519632466: do_socket: Received header Proxy-Connection = Keep-Alive
Process-1: Thread_0: 1519632466: do_socket: Received header Connection = Keep-Alive
Process-1: Thread_0: 1519632466: do_socket: Received header Content-Length = 2549
Process-1: Thread_0: 1519632466: do_socket: Reading response data
Process-1: Thread_0: 1519632466: do_socket: Content length 2549
Process-1: Thread_0: 1519632466: do_transaction: Auth required
Process-1: Thread_0: 1519632466: do_transaction: Didn't get challenge, not NTLM proxy
Process-1: Thread_0: 1519632466: do_CONNECT: Error 407
Process-1: Thread_0: 1519632466: log_message: code 407, message Proxy Authentication Required
Process-1: Thread_0: 1519632466: log_message: "CONNECT github.com:443 HTTP/1.1" 407 -
Process-1: Thread_0: 1519632466: do_CONNECT: Transferred 0 bytes
Process-1: Thread_0: 1519632466: do_CONNECT: Done

And this is from an older 0.2 release:

Process-1: MainThread: 1519632294: verify_request: Client address: 127.0.0.1
Process-1: Thread_0: 1519632294: do_CONNECT: Entering
Process-1: Thread_0: 1519632294: do_transaction: Entering
Process-1: Thread_0: 1519632294: get_response_wkb: winkerberos SSPI
Process-1: Thread_0: 1519632294: do_socket: Entering
Process-1: Thread_0: 1519632294: do_socket: New connection
Process-1: Thread_0: 1519632294: do_socket: b'CONNECT github.com:443 HTTP/1.1\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'Host: github.com:443\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'User-Agent: git/2.15.0.windows.1\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'Proxy-Connection: Keep-Alive\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending extra b'Proxy-Authorization: NTLM TlRMTVNTUAABAAAAl7II4gUA... and much more... BMDY1M0dST1VQ\r\n'
Process-1: Thread_0: 1519632294: do_socket: Reading response code
Process-1: Thread_0: 1519632294: do_socket: Response code: 407 False
Process-1: Thread_0: 1519632294: do_socket: Reading response headers
Process-1: Thread_0: 1519632294: do_socket: Received header Proxy-Authenticate = NTLM TlRMTVNTUAACAAAACgAKADgAAAAV... and much more... ABwAIAPmST3zYrtMBAAAAAA==
Process-1: Thread_0: 1519632294: do_socket: Received header Cache-Control = no-cache
Process-1: Thread_0: 1519632294: do_socket: Received header Pragma = no-cache
Process-1: Thread_0: 1519632294: do_socket: Received header Content-Type = text/html; charset=utf-8
Process-1: Thread_0: 1519632294: do_socket: Received header Proxy-Connection = Keep-Alive
Process-1: Thread_0: 1519632294: do_socket: Received header Connection = Keep-Alive
Process-1: Thread_0: 1519632294: do_socket: Received header Content-Length = 2549
Process-1: Thread_0: 1519632294: do_socket: Reading response data (nobody: False)
Process-1: Thread_0: 1519632294: do_socket: Content length 2549
Process-1: Thread_0: 1519632294: do_transaction: Auth required
Process-1: Thread_0: 1519632294: do_transaction: Challenged
Process-1: Thread_0: 1519632294: get_response_wkb: winkerberos SSPI
Process-1: Thread_0: 1519632294: do_socket: Entering
Process-1: Thread_0: 1519632294: do_socket: b'CONNECT github.com:443 HTTP/1.1\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'Host: github.com:443\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'User-Agent: git/2.15.0.windows.1\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending b'Proxy-Connection: Keep-Alive\r\n'
Process-1: Thread_0: 1519632294: do_socket: Sending extra b'Proxy-Authorization: NTLM TlRMTVNTUAADAAAAGAAYAIIAAA... and much more... J2HBxQa\r\n'
Process-1: Thread_0: 1519632294: do_socket: Reading response code
Process-1: Thread_0: 1519632294: do_socket: Response code: 200 True
Process-1: Thread_0: 1519632294: do_socket: Reading response headers
Process-1: Thread_0: 1519632294: do_socket: Reading response data (nobody: True)
Process-1: Thread_0: 1519632294: do_CONNECT: Tunneling through proxy
127.0.0.1 - - [26/Feb/2018 09:04:54] "CONNECT github.com:443 HTTP/1.1" 200 -
Process-1: Thread_0: 1519632295: do_CONNECT: Transferred 6094 bytes
Process-1: Thread_0: 1519632295: do_CONNECT: Done

Any idea!? This might be related to #22.