The host is review-test.opendev.org, so hostvars for
review-test.openstack.org are not so much going to do anything.
It's easier if we just ssh as root from review to gerrit2
on review-test.
review-test needs to be in letsencrypt group and have a
handler.
We need to install mysql - it's on the existing review
servers but not in ansible, it's just left over from
puppet.
The db credentials are in /root/.gerrit_db.cnf
Change-Id: I90e3c9d1b398cc16fea9f7056cfb059c7140160e
4aa28fee13