Command names should be lower-case.  Enforce this.  Fix the fixable
offenders (all in tests/), and add the remainder to pragma
command-name-exceptions.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210323094025.3569441-25-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>