Fixed IndexOutOfBoundsException in ZookeeperRegistry
diff --git a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
index d46b42e..b9d04d4 100644
--- a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
+++ b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
@@ -312,6 +312,10 @@
 				}
 			);
 		
+		if (sortedData.size() == 0){
+			return null;
+		}
+		
 		return new String(sortedData.get(0).getData(), Charsets.UTF_8);
 	}