You do not need to have OpenStack preinstalled. The Ansible script will install OpenStack Kilo.
I have seen the script get stuck during the sql installation a small number of times. I am unsure how it gets into this state. When you installed 14.04, was it a clean install?
What you could try is to remove mariadb-server, and then rerun the script again:
apt-get remove mariadb-server