Support enabling early data on SSL

This moves the early data switch to CERT to make this
|SSL_set_SSL_CTX|-proof.

Change-Id: Icca96e76636d87578deb24b2d507cabee7e46a4a
Reviewed-on: https://boringssl-review.googlesource.com/14545
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/tls13_server.c b/ssl/tls13_server.c
index 35ee4f7..500cb9d 100644
--- a/ssl/tls13_server.c
+++ b/ssl/tls13_server.c
@@ -167,7 +167,7 @@
       goto err;
     }
 
-    if (ssl->ctx->enable_early_data) {
+    if (ssl->cert->enable_early_data) {
       session->ticket_max_early_data = kMaxEarlyDataAccepted;
 
       CBB early_data_info;
@@ -355,7 +355,7 @@
       hs->new_session = SSL_SESSION_dup(session, SSL_SESSION_DUP_AUTH_ONLY);
 
       if (/* Early data must be acceptable for this ticket. */
-          ssl->ctx->enable_early_data &&
+          ssl->cert->enable_early_data &&
           session->ticket_max_early_data != 0 &&
           /* The client must have offered early data. */
           hs->early_data_offered &&