Simplify tls1_channel_id_hash.

Rather than iterate over handshake_dgsts itself, it can just call
tls1_handshake_digest.

Change-Id: Ia518da540e47e65b13367eb1af184c0885908488
Reviewed-on: https://boringssl-review.googlesource.com/5617
Reviewed-by: Adam Langley <agl@google.com>
4 files changed