Fix test for MySQL
Fix test for MySQL

OK, I tested for SQLite3 and PostgreSQL but didn’t for MySQL :trollface:

This is quick but should probably be converted back to `quote_` format
like elsewhere in the test suite.

martndemus/ransack,AndrewSwerlick/ransack,roman-franko/ransack,reinteractive/ransack,activerecord-hackery/ransack,guilleva/ransack,outstand/ransack,johan--/ransack,Mario245/ransack,avit/ransack,laserlemon/ransack,mariorcardoso/ransack,Eric-Guo/ransack