Throw InternalFailure in catch

Throw an InternalFailure if unable to get the MAC
Address from Inventory.

Change-Id: I35f089bcb53ad1796a257a083a9b7ab67b0af496
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/ethernet_interface.cpp b/ethernet_interface.cpp
index af8efc9..04f9009 100644
--- a/ethernet_interface.cpp
+++ b/ethernet_interface.cpp
@@ -719,7 +719,7 @@
         {
             log<level::ERR>("Exception occurred during getting of MAC "
                             "address from Inventory");
-            return  MacAddressIntf::mACAddress();
+            elog<InternalFailure>();
         }
     }
     auto interface = interfaceName();