validate which key is being used/deleted

Author: ldetmer

auth/src/test/java/com/google/cloud/auth/samples/AuthExampleIT.java

@@ -70,6 +70,7 @@ public void testAuthApiKey() throws IOException, IllegalStateException {
     Key apiKey = null;
     try {
       apiKey = AuthTestUtils.createTestApiKey(projectId, keyDisplayName, service, method);
+      assertNotNull(apiKey)
       System.out.println("created key " + apiKey.getKeyString());
       String output = ApiKeyAuthExample.authenticateUsingApiKey(apiKey.getKeyString());