Added code to intent unit tests to pre-emptively unbind ID generator to avoid cascading failures.

Change-Id: I2e5aff44a90ceeaaad71d7154b79f20edab620a7
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java b/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
index 68304eb..d939f96 100644
--- a/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/IntentManager.java
@@ -167,6 +167,7 @@
         batchExecutor = newSingleThreadExecutor(groupedThreads("onos/intent", "batch", log));
         workerExecutor = newFixedThreadPool(numThreads, groupedThreads("onos/intent", "worker-%d", log));
         idGenerator = coreService.getIdGenerator("intent-ids");
+        Intent.unbindIdGenerator(idGenerator);
         Intent.bindIdGenerator(idGenerator);
         log.info("Started");
     }