The ops should be checked if it is null.

Change-Id: If91582add24334427c4b9f935cec622a6e7d8f6d
diff --git a/pipelines/fabric/src/main/java/org/onosproject/pipelines/fabric/pipeliner/FabricPipeliner.java b/pipelines/fabric/src/main/java/org/onosproject/pipelines/fabric/pipeliner/FabricPipeliner.java
index 7cd154b..7b3006d 100644
--- a/pipelines/fabric/src/main/java/org/onosproject/pipelines/fabric/pipeliner/FabricPipeliner.java
+++ b/pipelines/fabric/src/main/java/org/onosproject/pipelines/fabric/pipeliner/FabricPipeliner.java
@@ -242,6 +242,9 @@
         }
 
         FlowRuleOperations ops = buildFlowRuleOps(objective, flowRules);
+        if (ops == null) {
+            return;
+        }
         flowRuleService.apply(ops);
 
         flowRules.forEach(flow -> {