[wikimo] fix object store token expired error in issue #87 (#89)

lib/weixin_authorize.rb

@@ -89,7 +89,7 @@ module WeixinAuthorize
     end
     end
 
 
     def calculate_expire(expires_in)
     def calculate_expire(expires_in)
-      Time.now + expires_in.to_i - key_expired
+      Time.now.to_i + expires_in.to_i - key_expired.to_i
     end
     end
 
 
   end
   end