migration/tls: Use qcrypto_tls_creds_check_endpoint()

Avoid accessing QCryptoTLSCreds internals by using
the qcrypto_tls_creds_check_endpoint() helper.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

migration/tls.c

@@ -49,11 +49,7 @@ migration_tls_get_creds(MigrationState *s,
                    s->parameters.tls_creds);
         return NULL;
     }
-    if (ret->endpoint != endpoint) {
-        error_setg(errp,
-                   "Expected TLS credentials for a %s endpoint",
-                   endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT ?
-                   "client" : "server");
+    if (!qcrypto_tls_creds_check_endpoint(ret, endpoint, errp)) {
         return NULL;
     }