Add Support For MariaDB to Python Scripts

Some stacks, such as BigInights, support MariaDB as the database for Hive. When upgrading from BigInights to another stack, such as HDP, this causes the following exception when starting the Hive service:

```resource_management.core.exceptions.ExecutionFailed: Execution of 'service mysqld stop' returned 5. Redirecting to /bin/systemctl stop  mysqld.service
Failed to stop mysqld.service: Unit mysqld.service not loaded.```

This looks to be caused by the hard-coded reliance of mysqld in the Python scripts.