Removed unnecessary import from DriverMetadataServiceAvailableTest.

Author: shustsud

bookkeeper-server/src/test/java/org/apache/bookkeeper/client/api/DriverMetadataServiceAvailableTest.java

@@ -20,7 +20,6 @@
  */
 package org.apache.bookkeeper.client.api;
 
-import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import org.apache.bookkeeper.conf.ClientConfiguration;
 import org.apache.bookkeeper.test.BookKeeperClusterTestCase;