Add powerOff utility function

Logs an error so the shutdown reason is known and then
does a hard power off.

Change-Id: I52e2d07668a777c0aacf5c269f2632fbd6f15246
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/utility.hpp b/utility.hpp
index a4df0cb..fdae252 100644
--- a/utility.hpp
+++ b/utility.hpp
@@ -70,6 +70,14 @@
     value = sdbusplus::message::variant_ns::get<T>(property);
 }
 
+/**
+ * Powers off the system and logs an error
+ * saying it was due to a power fault.
+ *
+ * @param[in] bus - D-Bus object
+ */
+void powerOff(sdbusplus::bus::bus& bus);
+
 }
 }
 }