Updating Key Schedule and KeyUpdate to draft 16.

This doesn't currently honor the required KeyUpdate response. That will
be done in a follow-up.

BUG=74

Change-Id: I750fc41278736cb24230303815e839c6f6967b6a
Reviewed-on: https://boringssl-review.googlesource.com/11412
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/ssl/tls13_server.c b/ssl/tls13_server.c
index be485a1..532b708 100644
--- a/ssl/tls13_server.c
+++ b/ssl/tls13_server.c
@@ -459,7 +459,7 @@
   if (!tls13_advance_key_schedule(ssl, kZeroes, hs->hash_len) ||
       !tls13_derive_traffic_secret_0(ssl) ||
       !tls13_set_traffic_key(ssl, type_data, evp_aead_seal,
-                             hs->traffic_secret_0, hs->hash_len)) {
+                             hs->server_traffic_secret_0, hs->hash_len)) {
     return ssl_hs_error;
   }
 
@@ -523,7 +523,7 @@
       !ssl->method->hash_current_message(ssl) ||
       /* evp_aead_seal keys have already been switched. */
       !tls13_set_traffic_key(ssl, type_data, evp_aead_open,
-                             hs->traffic_secret_0, hs->hash_len) ||
+                             hs->client_traffic_secret_0, hs->hash_len) ||
       !tls13_finalize_keys(ssl)) {
     return ssl_hs_error;
   }