Prefer 'on' | 'off' over 'yes' | 'no' for bool options

Update some docs and test cases to use 'on' | 'off' as the preferred
value for bool options.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
4 files changed