Revise hash management for reading the Finished message.

Upstream originally sampled the Finished message's hash at ChangeCipherSpec,
but our patches to add messages between the two complicated this. Move DTLS to
this path, but use the new SSL_GET_MESSAGE_DONT_HASH_MESSAGE flag to avoid
special-casing message types in ssl3_get_message.

Change-Id: I9c8ddd9cc500c94dff2ec2f696f89d50ab01b3ad
Reviewed-on: https://boringssl-review.googlesource.com/1632
Reviewed-by: Adam Langley <agl@google.com>
2 files changed