Update exists.php

Author: yuduanchen

example/exists.php

@@ -1,12 +1,10 @@
 <?php
 
 try {
-    $obj = new phdfs();
-    $obj->port = "9000";
-    $obj->ip = "127.0.0.1";
+    $obj = new phdfs("127.0.0.1","9000");
     $obj->connect();
     $log = $obj->exists('/test.txt');
 } catch (Exception $ex) {
     var_dump($ex->getMessage());
 }
-?>
+?>