Actually update the keys when a KeyUpdate message is sent or received

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2609)
diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 909b2f0..88d7608 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -735,6 +735,9 @@
     case TLS_ST_CW_KEY_UPDATE:
         if (statem_flush(s) != 1)
             return WORK_MORE_A;
+
+        if (!tls13_update_key(s, 1))
+            return WORK_ERROR;
         break;
     }