ZOOKEEPER-1798. Fix race condition in testNormalObserverRun (Part 2) (thawan, fpj via thawan)

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1541814 13f79535-47bb-0310-9956-ffa450edef68

src/java/main/org/apache/zookeeper/server/quorum/ObserverZooKeeperServer.java

@@ -136,4 +136,12 @@ public class ObserverZooKeeperServer extends LearnerZooKeeperServer {
     public String getState() {
         return "observer";
     };    
+
+    @Override
+    public void shutdown() {
+        super.shutdown();
+        if (syncRequestProcessorEnabled && syncProcessor != null) {
+            syncProcessor.shutdown();
+        }
+    }
 }