mariadb: add datadir argument to mysqld_safe command

This addresses an issue where MariaDB would not load databases upon
first starting after a system reboot.

Closes #28987.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
mysql: add datadir argument to mysqld_safe command

This addresses a potential issue where MySQL may not load databases upon
first starting after a system reboot. Copied from an identical fix
required for MariaDB, where this behavior was first noticed.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>