minor, allow DebugTomcat on sandbox in different LAN

Author: lidongsjtu

examples/test_case_data/sandbox/hdfs-site.xml

@@ -15,6 +15,10 @@
   limitations under the License.
 -->
 <configuration>
+    <property>
+        <name>dfs.client.use.datanode.hostname</name>
+        <value>true</value>
+    </property>
 
     <property>
         <name>dfs.block.access.token.enable</name>