bug fix: NPE in hazelcast multiRead

- Correctly handle value does not exist in table error case.

Change-Id: I4d3c190f7fdeca29723fda7d8fb1a060a11e289d
diff --git a/src/main/java/net/onrc/onos/core/datastore/hazelcast/HZMultiEntryOperation.java b/src/main/java/net/onrc/onos/core/datastore/hazelcast/HZMultiEntryOperation.java
index 0a7fc5e..d3df22c 100644
--- a/src/main/java/net/onrc/onos/core/datastore/hazelcast/HZMultiEntryOperation.java
+++ b/src/main/java/net/onrc/onos/core/datastore/hazelcast/HZMultiEntryOperation.java
@@ -124,9 +124,14 @@
     private VersionedValue get() {
         try {
             VersionedValue value = future.get();
-            setValue(value.getValue(), value.getVersion());
-            setStatus(STATUS.SUCCESS);
-            return value;
+            if (value == null) {
+                setStatus(STATUS.FAILED);
+                return null;
+            } else {
+                setValue(value.getValue(), value.getVersion());
+                setStatus(STATUS.SUCCESS);
+                return value;
+            }
         } catch (CancellationException | InterruptedException | ExecutionException e) {
             log.error(this + " has failed.", e);
             setStatus(STATUS.FAILED);