MDEV-38244 Remove deprecated hashicorp_key_management_cache_timeout and hashicorp_key_management_use_cache_on_timeout

[longjinvan]

Description

Remove the deprecated system variables hashicorp_key_management_cache_timeout and hashicorp_key_management_use_cache_on_timeout from the Hashicorp Key Management plugin.

Release Notes

N/A

How can this PR be tested?

• All MTR tests pass.
• Verify that the removed system variables (hashicorp_key_management_cache_timeout and hashicorp_key_management_use_cache_on_timeout) are no longer visible:

Before the fix

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE "hashicorp%";
+------------------------------------------------+---------------------------------------+
| Variable_name                                  | Value                                 |
+------------------------------------------------+---------------------------------------+
| hashicorp_key_management_cache_timeout         | 9223372036854775807                   |
| hashicorp_key_management_cache_version_timeout | 60000                                 |
| hashicorp_key_management_caching_enabled       | ON                                    |
| hashicorp_key_management_check_kv_version      | ON                                    |
| hashicorp_key_management_max_retries           | 3                                     |
| hashicorp_key_management_timeout               | 15                                    |
| hashicorp_key_management_use_cache_on_timeout  | ON                                    |
| hashicorp_key_management_vault_ca              |                                       |
| hashicorp_key_management_vault_url             | http://127.0.0.1:8200/v1/mariadbtest/ |
+------------------------------------------------+---------------------------------------+
9 rows in set (0.001 sec)

After the fix

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE "hashicorp%";
+------------------------------------------------+---------------------------------------+
| Variable_name                                  | Value                                 |
+------------------------------------------------+---------------------------------------+
| hashicorp_key_management_cache_version_timeout | 60000                                 |
| hashicorp_key_management_caching_enabled       | ON                                    |
| hashicorp_key_management_check_kv_version      | ON                                    |
| hashicorp_key_management_max_retries           | 3                                     |
| hashicorp_key_management_timeout               | 15                                    |
| hashicorp_key_management_vault_ca              |                                       |
| hashicorp_key_management_vault_url             | http://127.0.0.1:8200/v1/mariadbtest/ |
+------------------------------------------------+---------------------------------------+
7 rows in set (0.001 sec)

Basing the PR against the correct MariaDB version

•  This is a code change to remove deprecated plugin variables for the 13.3 release, and the PR is based against the latest MariaDB development branch.

Copyright

All new code of the whole pull request, including one or several files that are either new files or modified ones, are contributed under the BSD-new license. I am contributing on behalf of my employer Amazon Web Services, Inc.

[gkodinov]

Thank you for your contribution! This is a preliminary review.

LGTM. Please stand by for the final review.