Remove unwarranted call to free()

Do not free() the pointer allocated by sd_bus_message_read(), because
systemd will free that once the message is unreferenced. The free() in
question here was causing an ipmid core dump.

Resolves openbmc/openbmc#2846.

Change-Id: I118f6947e7292b68744d0034c72572e4dcb99f01
Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
diff --git a/sensorhandler.cpp b/sensorhandler.cpp
index 9064ecc..c8505e7 100644
--- a/sensorhandler.cpp
+++ b/sensorhandler.cpp
@@ -573,7 +573,6 @@
                 resp->indication[0] = 0x1;
             }
             resp->indication[1] = 0;
-            free(assertion);
             break;
 
         case IPMI_SENSOR_TEMP: