Update pgbouncer failover to stop the correct db in case of split brain
Summary
Cannot shutdown pgbouncer databases other than the default gitlabhq_production
in the case of a split brain. This currently impacts users who have changed the database name, and users who have setup a geo tracking database with our patroni setup.
Proposal
Update the database we shutdown in a split brain scenario to match gitlab_rails['db_database']
https://gitlab.com/gitlab-org/omnibus-gitlab/-/blob/388521001251f26b327d665200fbbd2ac9966d8b/files/gitlab-cookbooks/consul/templates/default/watcher_scripts/failover_pgbouncer.erb#L75
Details
When a database splitbrain occurs, GitLab's managed pgbouncer failover script attempts to shut down the pgbouncer database to help reduce the number of transactions that are going to a leader server. Patroni will also at the same time be working to shutdown postgres so it can't recieve the transactions, but this shutdown may time some time, or fail. (See https://github.com/zalando/patroni/blob/master/docs/watchdog.rst#watchdog-support)