Under certain circumstances nutshutdown was causing a forced
shutdown of the UPS even though killpower was not indicated.
Prevent that.  Also clarify the logic for powering off server
by avoiding && || chains.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>

Forced shutdown of the UPS was not actually happening before
due to lack of specific commands doing the shutdown.  This
(and the nut-driver initscript) fix that.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>