RE: make pg_createsubscriber option names more consistent

Dear Peter,

> I propose to rename the pg_createsubscriber option --socket-directory to
> --socketdir.  This would make it match the equivalent option in
> pg_upgrade.  (It even has the same short option '-s'.)
> pg_createsubscriber and pg_upgrade have a lot of common terminology and
> a similar operating mode, so it would make sense to keep this consistent.

+1. If so, should we say "default current dir." instead of "default current directory" in usage()
because pg_upgrade says like that?

Best regards,
Hayato Kuroda
FUJITSU LIMITED