All perfect. I rename the files.
root@d7:/home/dac# mv -f /etc/mysql/my.cnf /etc/mysql/my.cnf.old
root@d7:/home/dac# ln -sf mariadb.cnf /etc/mysql/my.cnf
Reboot server.
And now is working
root@d7:/home/dac# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 40
Server version: 10.0.17-MariaDB-1~exp2 (Debian)
Copyright (c) 2000, 2015, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>