MariaDB no longer reads /etc/mysql/my.cnf

Hello,

MariaDB should search 3 locations for a config files:
/etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf

However it only does 2 now, ommiting /etc/mysql/my.cnf

In RHEL there is a MariaDB 5.5 in base, which reads all of the three locations.
In addition there are software collections which makes 10.2 and 10.3 available for the customers. The 10.3 version reads only 2 locations and also says such in the "mysqld --help --verbose"

I'd love to get it either fixed so it will accept all of the 3 locations as usual, or properly reasonably documented, why it was removed.

Downstream tracker (RedHat Bugzilla): #598173

Hint from IRC discussion:
It * could * be in MariaDB source for RPM builds only.
Thus not reproducible without RPM packages.

Fast command to check the mysqld help:

/usr/libexec/mysqld --help --verbose | grep --after=1 '^Default options' | tail -n 1