We add the new host so that it will get configured as a gitea backend
server. We exclude this server from the list of gitea hosts to configure
git repos on because we want to recover its DB from one of the other
sibling nodes first. This should preserve the http redirects for us.
Once we have the db recovered we can enable replication from gerrit then
readd this host to the haproxy load balancer.
Change-Id: Ia2a98e5ded43cad044db36ca8d0da5a96277afee
3734f000f9