Update slh_dsa_test.c

Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26916)

test/slh_dsa_test.c

@@ -312,7 +312,7 @@ static EVP_PKEY *do_gen_key(const char *alg,
             || !TEST_int_eq(EVP_PKEY_CTX_set_params(ctx, params), 1)
             || !TEST_int_eq(EVP_PKEY_generate(ctx, &pkey), 1))
         pkey = NULL;
-err:
+
     EVP_PKEY_CTX_free(ctx);
     return pkey;
 }