Fix Geo PostgreSQL FDW not working with pgbouncer
When Geo uses a foreign server that is in front of pgbouncer, Rails database statements fail because pgbouncer doesn't propagate the default PostgreSQL schema_path.
pgbouncer won't ever support this (see https://github.com/pgbouncer/pgbouncer/issues/89), so we should force Rails to set the proper path each time.
Closes gitlab-org/gitlab-ee#4522
Edited by Stan Hu