DistributedFlowRuleStore related fixes

- handle no master for Device case
- Changed failed item type to FlowRule

Change-Id: If6c85751759cf6ba9ab0ed0384cbe1bf08a5d572
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/CompletedBatchOperation.java b/core/api/src/main/java/org/onlab/onos/net/flow/CompletedBatchOperation.java
index e78ebe0..3758ea9 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/CompletedBatchOperation.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/CompletedBatchOperation.java
@@ -19,13 +19,13 @@
 
 import com.google.common.collect.ImmutableSet;
 
-public class CompletedBatchOperation implements BatchOperationResult<FlowEntry> {
+public class CompletedBatchOperation implements BatchOperationResult<FlowRule> {
 
 
     private final boolean success;
-    private final Set<FlowEntry> failures;
+    private final Set<FlowRule> failures;
 
-    public CompletedBatchOperation(boolean success, Set<FlowEntry> failures) {
+    public CompletedBatchOperation(boolean success, Set<? extends FlowRule> failures) {
         this.success = success;
         this.failures = ImmutableSet.copyOf(failures);
     }
@@ -36,7 +36,7 @@
     }
 
     @Override
-    public Set<FlowEntry> failedItems() {
+    public Set<FlowRule> failedItems() {
         return failures;
     }