Twitch login fails with a 404 (easy fix)

[rhettlunn]

It looks like twitch has changed their login system, but from my testing there's an easy fix:
(in extractor/twitch.py)
_LOGIN_POST_URL = 'https://passport.twitch.tv/authentications/new'

Anonymized debug output:
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'--hls-prefer-native', u'-u', u'PRIVATE', u'-p', u'PRIVATE', u'PRIVATE']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2015.08.16.1
[debug] Python version 2.7.8 - Windows-7-6.1.7601-SP1
[debug] exe versions: none
[debug] Proxy map: {}
[twitch:vod] Downloading login page
[twitch:vod] Logging in as PRIVATE
ERROR: Unable to download webpage: HTTP Error 404: Not Found (caused by HTTPError()); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
File "youtube_dl\extractor\common.pyo", line 326, in _request_webpage
File "youtube_dl\YoutubeDL.pyo", line 1860, in urlopen
File "urllib2.pyo", line 410, in open
File "urllib2.pyo", line 523, in http_response
File "urllib2.pyo", line 448, in error
File "urllib2.pyo", line 382, in _call_chain
File "urllib2.pyo", line 531, in http_error_default