Drop explicit check for engines in opt_legacy_okay

The providers indication should always indicate that this is not a
legacy request.
This makes a check for engines redundant as the default return is that
legacy is ok if there are no explicit providers.

Fixes #19662

Signed-off-by: Simo Sorce <simo@redhat.com>

apps/lib/apps.c

@@ -3405,14 +3405,6 @@ int opt_legacy_okay(void)
 {
     int provider_options = opt_provider_option_given();
     int libctx = app_get0_libctx() != NULL || app_get0_propq() != NULL;
-#ifndef OPENSSL_NO_ENGINE
-    ENGINE *e = ENGINE_get_first();
-
-    if (e != NULL) {
-        ENGINE_free(e);
-        return 1;
-    }
-#endif
     /*
      * Having a provider option specified or a custom library context or
      * property query, is a sure sign we're not using legacy.

test/recipes/20-test_legacy_okay.t

@@ -0,0 +1,23 @@
+#! /usr/bin/env perl
+# Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the Apache License 2.0 (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+
+use strict;
+use warnings;
+
+use OpenSSL::Test;
+
+setup("test_legacy");
+
+plan tests => 3;
+
+ok(run(app(['openssl', 'rand', '-out', 'rand.txt', '256'])), "Generate random file");
+
+ok(run(app(['openssl', 'dgst', '-sha256', 'rand.txt'])), "Generate a digest");
+
+ok(!run(app(['openssl', 'dgst', '-sha256', '-propquery', 'foo=1',
+             'rand.txt'])), "Fail to generate a digest");