Sonar suggestions - fixes to potential null pointer dereferences

Change-Id: I4e350a9d72a9322971d5d4f831f1bdf167986b87
diff --git a/apps/optical-model/src/main/java/org/onosproject/net/optical/config/OpticalPortOperator.java b/apps/optical-model/src/main/java/org/onosproject/net/optical/config/OpticalPortOperator.java
index f9ee752..ee5ac99 100644
--- a/apps/optical-model/src/main/java/org/onosproject/net/optical/config/OpticalPortOperator.java
+++ b/apps/optical-model/src/main/java/org/onosproject/net/optical/config/OpticalPortOperator.java
@@ -93,7 +93,7 @@
         }
 
         OpticalPortConfig opc = lookupConfig(cp);
-        if (opc == null) {
+        if (descr == null || opc == null) {
             return descr;
         }