ensure power status is always correct

There's a slight bug here in that anytime determineStatusOfPower() is
called, the PowerStatus was set to Good for a period of time. This can
cause confusion on clients monitoring the property. Instead of
defaulting it to good, set it after the true status is known.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: If48eb5bd1c2bd94d51d12aff54a186aba295b179
diff --git a/chassis_state_manager.hpp b/chassis_state_manager.hpp
index e82a4cd..82ad2d1 100644
--- a/chassis_state_manager.hpp
+++ b/chassis_state_manager.hpp
@@ -100,13 +100,17 @@
 
     /** @brief Determine status of power provided by an Uninterruptible Power
      *         Supply into the system
+     *
+     *  @return True if UPS power is good, false otherwise
      */
-    void determineStatusOfUPSPower();
+    bool determineStatusOfUPSPower();
 
     /** @brief Determine status of power provided by the power supply units into
      *         the system
+     *
+     *  @return True if PSU power is good, false otherwise
      */
-    void determineStatusOfPSUPower();
+    bool determineStatusOfPSUPower();
 
     /**
      * @brief subscribe to the systemd signals