sql: errors in client due to use of pg_catalog with non-existent db as current #23893
Description
It seems there is a regression with the latest v2 alpha (20180312) as I am now seeing the following error when Ecto is trying to create the DB from scratch:
** (Postgrex.Error) ERROR 3D000 (invalid_catalog_name): database "postgres" does not exist
(db_connection) lib/db_connection/connection.ex:148: DBConnection.Connection.connect/2
(connection) lib/connection.ex:622: Connection.enter_connect/5
(stdlib) proc_lib.erl:247: :proc_lib.init_p_do_apply/3