Simplify Redfish error message property interface

The error message code used a json_pointer object which must
begin with a '/' character and had to be sent as an extra
parameter.  This change simplifies the interface by using a
string so there doesn't have to be a '/'.  This allowed the
same property argument passed for the message to be used
for the property field path.

Tested: Sent an error with a property and verified that it is
correctly displayed.

Change-Id: I0571e2eee627cedf29d751588a4f1bceee66f084
Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
diff --git a/redfish-core/lib/systems.hpp b/redfish-core/lib/systems.hpp
index 4ab4eb9..a1fbd0a 100644
--- a/redfish-core/lib/systems.hpp
+++ b/redfish-core/lib/systems.hpp
@@ -782,8 +782,8 @@
             }
             else
             {
-                messages::propertyValueNotInList(
-                    res, *indicatorLed, "IndicatorLED", "IndicatorLED");
+                messages::propertyValueNotInList(res, *indicatorLed,
+                                                 "IndicatorLED");
                 return;
             }