Fix a possible memory leak in ossl_x509_algor_md_to_mgf1

Add a missing check of the return code of X509_ALGOR_set0.
otherwise a memory leak may occur.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #22999)

(cherry picked from commit 493d6c9)

crypto/asn1/x_algor.c

@@ -179,7 +179,11 @@ int ossl_x509_algor_md_to_mgf1(X509_ALGOR **palg, const EVP_MD *mgf1md)
     *palg = X509_ALGOR_new();
     if (*palg == NULL)
         goto err;
-    X509_ALGOR_set0(*palg, OBJ_nid2obj(NID_mgf1), V_ASN1_SEQUENCE, stmp);
+    if (!X509_ALGOR_set0(*palg, OBJ_nid2obj(NID_mgf1), V_ASN1_SEQUENCE, stmp)) {
+        X509_ALGOR_free(*palg);
+        *palg = NULL;
+        goto err;
+    }
     stmp = NULL;
  err:
     ASN1_STRING_free(stmp);