PDI CS Bulk Load plugin can't work with variable defined in kettle.properties file

CS Bulk Loader can't work with variable for ColumnStore XML file path defined in the kettle.properties.

1. Open PDI spoon tool and open test.kjb
2. Open export-to-mariadb transformation object.
3. In Spoon main menu select Edit > Edit the kettle.properties file
4. Click right mouse button and select one of Insert options.
5. In new empty line add Variable name = DATABASE_CS_XML and Value = /home/pentaho/Downloads/test-job/Columnstore.xml (this is only an example for correct path to the file)
6. In export-to-mariadb transformation > MariaDB ColumnStore Bulk Loader component > Settings change ColumnStore XML field to use DATABASE_CS_XML variable
7. Save all changes
8. Run the test.kjb

Result:
Job fails with error

2018/03/09 16:25:11 - MariaDB ColumnStore Bulk Loader.0 - ERROR (version 8.0.0.0-28, build 8.0.0.0-28 from 2017-11-05 07.27.50 by buildguy) : The ColumnStoreDriver couldn't be instantiated.

2018/03/09 16:25:11 - MariaDB ColumnStore Bulk Loader.0 - ERROR (version 8.0.0.0-28, build 8.0.0.0-28 from 2017-11-05 07.27.50 by buildguy) : Error initializing step [MariaDB ColumnStore Bulk Loader]

If user tries to edit the bulk loader component again the following message is displayed:
Please select a valid Columnstore.xml file to proceed.

Expected:
Job finishes successfully if variable for columstore.xml file path is used.