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

Change-Id: I2e5aff44a90ceeaaad71d7154b79f20edab620a7
diff --git a/core/api/src/test/java/org/onosproject/net/intent/IntentServiceTest.java b/core/api/src/test/java/org/onosproject/net/intent/IntentServiceTest.java
index e4d906b..1bafca8 100644
--- a/core/api/src/test/java/org/onosproject/net/intent/IntentServiceTest.java
+++ b/core/api/src/test/java/org/onosproject/net/intent/IntentServiceTest.java
@@ -47,6 +47,7 @@
     public void setUp() {
         service = createIntentService();
         service.addListener(listener);
+        Intent.unbindIdGenerator(idGenerator);
         Intent.bindIdGenerator(idGenerator);
     }