Fix IPMI SEL sensor numbers

The IPMI SEL sensor numbers are off by one because the SEL assumed
that sensor numbers start at 1 when they actually start at 0.

Tested:
Confirmed that the sensor number in a SEL event matches the number
for that sensor in the SDR.

Change-Id: I3e205a89cd6bb3529b0fbe937058dee75c7acc62
Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
diff --git a/include/sdrutils.hpp b/include/sdrutils.hpp
index 89b64ac..8969bd6 100644
--- a/include/sdrutils.hpp
+++ b/include/sdrutils.hpp
@@ -121,7 +121,7 @@
 
     sensorNumMapPtr = std::make_shared<SensorNumMap>();
 
-    uint8_t sensorNum = 1;
+    uint8_t sensorNum = 0;
     for (const auto& sensor : *sensorTree)
     {
         sensorNumMapPtr->insert(