This sets both LC_COLLATE and LC_CTYPE with one option.  Similar
behavior is already supported in initdb, CREATE COLLATION, and
createdb.
Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/d9d5043a-dc70-da8a-0166-1e218e6e34d4%402ndquadrant.com