Fix crash on captcha

Author: python273

vk_api/vk_api.py

@@ -475,6 +475,8 @@ def __init__(self, vk, captcha_sid,
         self.args = args or ()
         self.kwargs = kwargs or {}
 
+        self.code = CAPTCHA_ERROR_CODE
+
         self.key = None
         self.url = url