Refactor IdBlcok: move to core.util package

Change-Id: Ibe0b3fe82d851a6549e33af1e4dc675f47a814b8
diff --git a/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java b/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java
index bf5612c..8683a50 100644
--- a/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java
+++ b/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java
@@ -15,6 +15,7 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.restserver.IRestApiService;
 import net.onrc.onos.core.registry.web.RegistryWebRoutable;
+import net.onrc.onos.core.util.IdBlock;
 import net.onrc.onos.core.util.OnosInstanceId;
 
 import org.apache.commons.lang.NotImplementedException;