Fix mock zookeeper change (#1674)

fix mock zookeeper change

(cherry picked from commit c43451a)

Author: coderzc

tests/src/test/java/io/streamnative/pulsar/handlers/mqtt/base/MQTTProtocolHandlerTestBase.java

@@ -18,7 +18,6 @@
 import static org.mockito.Mockito.spy;
 import com.google.common.base.Joiner;
 import com.google.common.collect.Sets;
-import com.google.common.util.concurrent.MoreExecutors;
 import io.netty.channel.EventLoopGroup;
 import io.streamnative.pulsar.handlers.mqtt.common.MQTTCommonConfiguration;
 import io.streamnative.pulsar.handlers.mqtt.common.utils.ConfigurationUtils;
@@ -415,7 +414,7 @@ protected void setupBrokerMocks(PulsarService pulsar) throws Exception {
     }
 
     public static MockZooKeeper createMockZooKeeper() throws Exception {
-        MockZooKeeper zk = MockZooKeeper.newInstance(MoreExecutors.newDirectExecutorService());
+        MockZooKeeper zk = MockZooKeeper.newInstance();
         zk.setSessionId(-1);
         List<ACL> dummyAclList = new ArrayList<>(0);