Minor update in PW configuration to handle updates better

Change-Id: I055592f8586b3b49539e87572d94f6af445003aa
diff --git a/src/test/java/org/onosproject/segmentrouting/PwaasConfigTest.java b/src/test/java/org/onosproject/segmentrouting/PwaasConfigTest.java
index 7686242..60163eb 100644
--- a/src/test/java/org/onosproject/segmentrouting/PwaasConfigTest.java
+++ b/src/test/java/org/onosproject/segmentrouting/PwaasConfigTest.java
@@ -303,9 +303,9 @@
         assertFalse(invalidConfigLabel.isValid());
     }
 
-    @Test(expected = IllegalArgumentException.class)
+    @Test
     public void testValid4() {
-        invalidConfigConflictingVlan.isValid();
+        assertFalse(invalidConfigConflictingVlan.isValid());
     }
 
     /**