Other elements can drop templates in a matching path to this to influence
the mysql configuration if need-be.

This file also serves as a place holder. my.cnf has an include line
which references it. The code in MySQL that implements the include bits
can't deal with an empty directory. We still want the conf.d though,
so that other elements can drop mysql configs in (such as a "mysql
go faster in dev" element which would disable InnoDB's sync-on-commit
durability protections).
