Fixed issue #60 on incorrect aggregate state initialization.

git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_dev_next@1226 123451ca-8445-de46-9d55-352943316053
diff --git a/hyracks-algebricks/hyracks-algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java b/hyracks-algebricks/hyracks-algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
index abfd1c1..ffc8c54 100644
--- a/hyracks-algebricks/hyracks-algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
+++ b/hyracks-algebricks/hyracks-algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/runtime/operators/aggreg/SerializableAggregatorDescriptorFactory.java
@@ -40,7 +40,7 @@
 
             @Override
             public AggregateState createAggregateStates() {
-                return null;
+                return new AggregateState();
             }
 
             @Override