adding log for error case

Change-Id: Id0f779ad951ef9d11f6b0afeda2d3cba9239f46a
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java b/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
index 65da61a..751f7ad 100644
--- a/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
@@ -31,8 +31,6 @@
 import org.onosproject.net.flow.FlowRule;
 import org.onosproject.net.flow.FlowRuleBatchEntry;
 import org.onosproject.net.flow.FlowRuleBatchOperation;
-import org.onosproject.net.flow.FlowRuleEvent;
-import org.onosproject.net.flow.FlowRuleListener;
 import org.onosproject.net.flow.FlowRuleOperations;
 import org.onosproject.net.flow.FlowRuleOperationsContext;
 import org.onosproject.net.flow.FlowRuleService;
@@ -312,6 +310,8 @@
             @Override
             public void onError(FlowRuleOperations ops) {
                 //FIXME store.write(pending.setState(BROKEN));
+                log.warn("Failed installation: {} {} on {}", pending.key(),
+                         pending.intent(), ops);
             }
         });
     }