Create an implementaion of IntentIdGenerator

- Define interface to allocate IdBlock in IdBlockAllocator
- Implement IdBlockAllocatorBasedIntentIdGenerator
- Refactor IdBlock class

Change-Id: I21fa21ae625e3d7e137a7f846bb5a0c1bdb8df9a
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 97e445f..bf5612c 100644
--- a/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java
+++ b/src/main/java/net/onrc/onos/core/registry/StandaloneRegistry.java
@@ -148,7 +148,7 @@
             long blockHead = blockTop;
             long blockTail = blockTop + BLOCK_SIZE;
 
-            IdBlock block = new IdBlock(blockHead, blockTail - 1, BLOCK_SIZE);
+            IdBlock block = new IdBlock(blockHead, BLOCK_SIZE);
             blockTop = blockTail;
 
             return block;