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/IntentDataTest.java b/core/api/src/test/java/org/onosproject/net/intent/IntentDataTest.java
index 77b9030..de215c6 100644
--- a/core/api/src/test/java/org/onosproject/net/intent/IntentDataTest.java
+++ b/core/api/src/test/java/org/onosproject/net/intent/IntentDataTest.java
@@ -55,6 +55,7 @@
     @Before
     public void setUpTest() {
         idGenerator = new MockIdGenerator();
+        Intent.unbindIdGenerator(idGenerator);
         Intent.bindIdGenerator(idGenerator);
 
         timestamp1 = new MockTimestamp(1);