bin/54692: `locale -k` with an invalid keyword exits with 0

[alex%strugee.net@localhost]

>Number:         54692
>Category:       bin
>Synopsis:       `locale -k` with an invalid keyword exits with 0
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 12 05:55:00 +0000 2019
>Originator:     AJ Jordan
>Release:        8.1
>Organization:
>Environment:
NetBSD localhost 8.1 NetBSD 8.1 (GENERIC) #0: Fri May 31 08:43:59 UTC 2019  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile GENERIC amd64
>Description:
Running `locale -k` with a keyword that doesn't exist doesn't work (because the keyword doesn't exist) but `locale` exits with 0 anyway. It should instead exit with a nonzero exit code.
>How-To-Repeat:
$ locale -k nonexistant && echo success
>Fix: