Move aead_{read,write}_ctx and next_proto_negotiated into ssl->s3.

Both are connection state rather than configuration state. Notably this
cuts down more of SSL_clear that can't just use ssl_free + ssl_new.

Change-Id: I3c05b3ae86d4db8bd75f1cd21656f57fc5b55ca9
Reviewed-on: https://boringssl-review.googlesource.com/6835
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 25d9916..2d0a4fb 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1311,14 +1311,14 @@
     return 0;
   }
 
-  OPENSSL_free(ssl->next_proto_negotiated);
-  ssl->next_proto_negotiated = BUF_memdup(selected, selected_len);
-  if (ssl->next_proto_negotiated == NULL) {
+  OPENSSL_free(ssl->s3->next_proto_negotiated);
+  ssl->s3->next_proto_negotiated = BUF_memdup(selected, selected_len);
+  if (ssl->s3->next_proto_negotiated == NULL) {
     *out_alert = SSL_AD_INTERNAL_ERROR;
     return 0;
   }
 
-  ssl->next_proto_negotiated_len = selected_len;
+  ssl->s3->next_proto_negotiated_len = selected_len;
   ssl->s3->next_proto_neg_seen = 1;
 
   return 1;