1.1.1: Fix MySQL file permission issue on Docker

Change

1. Fix issue of no directory logging in with home=/ on MySQL 5.7 x Docker containers #9.

Reference

• Travis CI: https://travis-ci.org/chusiang/testlink.ansible.role/builds/368179479

  This change only for build docker images on Docker Hub, so it will effect the Travis CI.

• Docker Hub:

  1. ubuntu-16.04: https://hub.docker.com/r/chusiang/testlink/builds/bnnfwyal46nemqeysategv4/
  2. debian-8: https://hub.docker.com/r/chusiang/testlink/builds/bwynqu6lfbt8ne3kwrat82r/