Include reason what caused NPE

Change-Id: Id28931b12cfc428c8941030ed5843805b6226de3
diff --git a/drivers/odtn-driver/src/main/java/org/onosproject/drivers/odtn/OpenConfigDeviceDiscovery.java b/drivers/odtn-driver/src/main/java/org/onosproject/drivers/odtn/OpenConfigDeviceDiscovery.java
index d59d5c0..1d5563a 100644
--- a/drivers/odtn-driver/src/main/java/org/onosproject/drivers/odtn/OpenConfigDeviceDiscovery.java
+++ b/drivers/odtn-driver/src/main/java/org/onosproject/drivers/odtn/OpenConfigDeviceDiscovery.java
@@ -152,8 +152,8 @@
 
         String name = component.getString("name");
         String type = component.getString("state/type");
-        checkNotNull(name);
-        checkNotNull(type);
+        checkNotNull(name, "name not found");
+        checkNotNull(type, "state/type not found");
         props.put(OdtnDeviceDescriptionDiscovery.OC_NAME, name);
         props.put(OdtnDeviceDescriptionDiscovery.OC_TYPE, type);