add backup uphost

Author: rwifeng

src/Qiniu/Storage/ResumeUploader.php

@@ -77,7 +77,7 @@ public function upload()
                 $ret = $response->json();
             }
             if ($response->statusCode < 0) {
-                $this->host = Config::UPBACKUP_HOST;
+                $this->host = $confg::$upBackupHost;
             }
             if ($response->needRetry() || !isset($ret['crc32']) || $crc != $ret['crc32']) {
                 $response = $this->makeBlock($data, $blockSize);

src/Qiniu/Zone.php

@@ -4,19 +4,32 @@
 final class Zone
 {
     public static $upHost = 'http://up.qiniu.com';
+    public static $upBackupHost = 'http://upload.qiniu.com';
 
-    public function __construct($upHost)
+    public function __construct()
     {
-        $this->upHost = $upHost;
+    }
+
+    public function setUpHost($host)
+    {
+        self::$upHost = $host;
+    }
+
+    public function setUpBackupHost($host)
+    {
+        self::$upBackupHost = $host;
     }
 
     public static function zone0()
     {
-        return new self('http://up.qiniu.com');
+        return new self;
     }
 
     public static function zone1()
     {
-        return new self('http://up-z1.qiniu.com');
+        $z1 = new self;
+        $z1->setUpHost('http://up-z1.qiniu.com');
+        $z1->setUpBackupHost('http://upload-z1.qiniu.com');
+        return $z1;
     }
 }