Implement extended master secret in tlslite (again)

Implement extended master secret in tlslite (again)

Originally implemented in https://codereview.chromium.org/1283373002/, was
reverted in https://codereview.chromium.org/1299153002/. This cl includes a fix
for the test that failed (SSLClientSocketOpenSSLClientAuthTest.SendGoodCert).

BUG=467312
Committed: https://crrev.com/be964395f338c3419cec900c43f61034040db825
Cr-Commit-Position: refs/heads/master@{#344520}

[nharper, 2015-08-20 02:51:26]

nharper@chromium.org changed reviewers:
+ davidben@chromium.org, jbudorick@chromium.org

[davidben, 2015-08-20 15:31:46]

lgtm

https://codereview.chromium.org/1306553002/diff/1/third_party/tlslite/tlslite...
File third_party/tlslite/tlslite/tlsrecordlayer.py (right):

https://codereview.chromium.org/1306553002/diff/1/third_party/tlslite/tlslite...
third_party/tlslite/tlslite/tlsrecordlayer.py:819: self._ems_handshake_hash =
self._getHandshakeHash()
Oh. That was the problem. Right. The dumb thing where the spec is unclear about
when to sample.

I think this would be better if the key exchange code gave you the master
secret, rather than the premaster, and then you don't need to save it. But the
way this code is organized, that would be kind of a mess with all the useless
key exchanges supported, so this is probably the easiest. I'm not going to ask
you to refactor this monster. :-)

Upstream would (rightly) complain, but I've mostly given up on trying to
upstream our patches. The code is too much of a mess and I don't really have the
time to rewrite it. :-)

[nharper, 2015-08-20 16:46:13]

The CQ bit was checked by nharper@chromium.org

[commit-bot: I haz the power, 2015-08-20 16:46:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306553002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306553002/1

[commit-bot: I haz the power, 2015-08-20 16:52:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-20 16:52:59]

Patchset 1 (id:??) landed as
https://crrev.com/be964395f338c3419cec900c43f61034040db825
Cr-Commit-Position: refs/heads/master@{#344520}