cater for property change signal to invalidate fru data

Resolves openbmc/openbmc#1560

Change-Id: I90897959dab76181a6006c372c4b60cc1bdd0c0c
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/read_fru_data.hpp b/read_fru_data.hpp
index f536cf2..d715858 100644
--- a/read_fru_data.hpp
+++ b/read_fru_data.hpp
@@ -18,5 +18,11 @@
  */
 const FruAreaData& getFruAreaData(const FRUId& fruNum);
 
+/**
+ * @brief Register callback handler into DBUS for PropertyChange events
+ *
+ * @return negative value on failure
+ */
+int registerCallbackHandler();
 } //fru
 } //ipmi