Fix ECDHE_PSK key exchange.

The current implementation switches the order of other_secret and psk;
other_secret is first. Fix it and rewrite with CBB instead. The server half got
fixed on accident in a prior refactor.

Change-Id: Ib52a756aadd66e4bf22c66794447f71f4772da09
Reviewed-on: https://boringssl-review.googlesource.com/2052
Reviewed-by: Adam Langley <agl@google.com>
1 file changed