[fetch] RequestCache "reload" type must also set no-cache headers (#201)

For `reload`, I think the UA needs to set the correct headers to signal to HTTP proxies that the request should not be served from cache.  Gecko does the following in this case:

* It sets the `Pragma: no-cache` request header.
* If the protocol is HTTP >= 1.1, it also sets the `Cache-Control: no-cache` request header.

I think this needs to be spec'ed, since otherwise an HTTP cache along the way will break the contract of the fetch API.

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/fetch/issues/201