Sync w/ updated power control interfaces

setPowerState/getPowerState methods are removed.
all properties are removed except PGood and State.
return value of forcePowerOff is changed to bool from int32

TestBy:
    Ipmi command and click buttons
Change-Id: I0b5e51cea959594acf04257c566893da6ffe7d26
Signed-off-by: Kuiying Wang <kuiying.wang@intel.com>
diff --git a/power-control/service-files/xyz.openbmc_project.Chassis.Control.Power@.service b/power-control/service-files/xyz.openbmc_project.Chassis.Control.Power@.service
index fe69931..3bbfb17 100644
--- a/power-control/service-files/xyz.openbmc_project.Chassis.Control.Power@.service
+++ b/power-control/service-files/xyz.openbmc_project.Chassis.Control.Power@.service
@@ -10,8 +10,8 @@
 ExecStart=/usr/bin/env power-control
 SyslogIdentifier=power-control
 Type=dbus
-BusName={BUSNAME}
+BusName=xyz.openbmc_project.Chassis.Control.Power
 
 [Install]
-WantedBy={SYSTEMD_DEFAULT_TARGET}
+WantedBy=obmc-standby.target