Do not have hardfail if MySQL driver not found

[jjg-123]

There is a bug in how drivers for MariaDB and MySQL work. In particular, if the MariDB driver is installed first (no control over that normally) it intercepts calls for the MySQL driver and since there are differences in the database, this can cause seriously strange errors. The fix in the Pool was to explicitly load the MySQL driver before anything else, however, now that more people are using Derby. That cuases a hard filure making it so the MySQL driver is a requirement regardless of how people are setting up their system.

Make a missing MySQL a benign error.