Postgres schema_search_path shouldn't be fixed to "public" in rake

schema_search_path is fixed to "public" in the testing environment, due to [this commit](https://github.com/rails/rails/commit/3fee2378edd45188e41a7d14d4ca0a88280b541e) in response to [this issue](https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/170-postgresql-update-rake-tasks-to-use-full-settings-from-database-yml-bugfix)

I'm working with a very complex postgres database, which must respect all of my postgres schemas in the test environment in order to adequately test. Forcing schema to always be "public" is very limiting.