mbedtls: client: check cert exists and is valid

It should be SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, but it was only SSL_VERIFY_FAIL_IF_NO_PEER_CERT, so it didn't verify the cert, it only checked its existence.

To fix that, turn on both just like openssl-server.c does.

lib/tls/mbedtls/mbedtls-server.c

@@ -39,7 +39,7 @@ lws_tls_server_client_cert_verify_config(struct lws_vhost *vh)
 	}
 
 	if (!lws_check_opt(vh->options, LWS_SERVER_OPTION_PEER_CERT_NOT_REQUIRED))
-		verify_options = SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
+		verify_options |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 
 	lwsl_notice("%s: vh %s requires client cert %d\n", __func__, vh->name,
 		    verify_options);