User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:36.0) Gecko/20100101 Firefox/36.0
Build Identifier: 

mariadb-10.0.13-2.6.1.x86_64
logrotate-3.8.7-6.1.2.x86_64
Enabling logrotate (systemctl enable logrotate.timer) and running it manually to debug it complain for that:
error: skipping "/var/log/mysql/mysqld.log" because parent directory has insecure permissions (It's world writable or writable by group which is not "root") Set "su" directive in config file to tell logrotate which user/group should be used for rotation.

I think it's a simple to correct this issue using root group as requested by logrotate. (I think it's to be modified /usr/lib/mysql/rcmysql ah it's the utility that create the /var/log/mysql/mysqld.log)

Reproducible: Always