Add a zookeeper compile dependency to fix build in maven

core/pom.xml

@@ -48,6 +48,10 @@
       <groupId>org.apache.avro</groupId>
       <artifactId>avro-ipc</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.zookeeper</groupId>
+      <artifactId>zookeeper</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.eclipse.jetty</groupId>
       <artifactId>jetty-server</artifactId>