Add support for handling SSL_CIPHER_ALGORITHM2_AEAD ciphers, which are
those that use EVP_AEAD instead ov EVP_CIPHER. This means being able to
change cipher state with an EVP_AEAD and being able to encrypt/decrypt
TLS using the EVP_AEAD. This has no change on existing
non-SSL_CIPHER_ALGORITHM2_AEAD ciphers.

Based on Adam Langley's chromium patches.

Rides the recent libssl bump.

Tested by sthen@