Geo: `geo:db:reset` rake task fails on dr.gitlab.com

It was observed the geo:db:reset was failing on dr.gitlab.com:

$ sudo gitlab-rake geo:db:reset
ERROR:  No such database: postgres
Couldn't drop database 'gitlabhq_geo_production'
rake aborted!
PG::ConnectionBad: ERROR:  No such database: postgres
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/gitlab/geo/database_tasks.rb:14:in `public_send'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/gitlab/geo/database_tasks.rb:14:in `block in method_missing'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/gitlab/geo/database_tasks.rb:181:in `with_geo_db'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/gitlab/geo/database_tasks.rb:13:in `method_missing'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:14:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:46:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'
Tasks: TOP => geo:db:drop
(See full trace by running task with --trace)

cc @devin, @abrandl, @geo-team