Proxy should reuse original request's Accept headers on redirects

When the proxy gets a redirect response from target resource, it doesn't reuse client's original Accept header on subsequent request following the Location. What ends up being returned to the client is inconsistent.

[It may be true for the other headers from the client are dropped as well, but Accept is up there on the list to make sure it works as expected.]

在仓库中搜索代理重定向处理和请求头转发，然后在发送 Accept 请求头的同时重现一次重定向。检查跟随 Location 后发出的请求，并验证客户端原始的 Accept 值是否得到保留；当重定向响应与原始请求一致时即表示完成。