force http1

[fulmicoton]

Disables http2 to fix bug with gcloud

Google cloud storage allows http2, but hyper's http2 client
does not seem to support it properly, leading to an error.

This PR manually disables http2.

Closes #1584

[saroh]

LGTM!
I can re raise the issue w/ rusoto and probably hyper-rustls or hyper (I haven't validated the presence of the host header tbh) WDYT ?
given hyper-tls is ok w/ http2
https://github.com/rusoto/rusoto/blob/master/rusoto/core/src/lib.rs#L22-L25
https://github.com/rusoto/rusoto/blob/master/rusoto/core/src/request.rs#L220-L260
https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.3
hyperium/h2#548 (comment)

[fmassot]

@saroh that would really nice to open an issue but it would be even better to check that it comes from some header.

[fulmicoton]

@saroh yes please! that would be awesome to get that fixed in rusoto. (that's more a rusoto problem than an hyper problem I think. Maybe I misunderstand the problem, but one root is that http2 is kind of leaking and not honoring its promise to work as a drop-in more efficient replacement to http1 from the client's client side.

It expects an Authority header and no Host in request headers. I am not sure what should be the best way for rusoto to deal with the problem tbh... One thing to note is that by default, hyper clients will populate the Host header automatically if it is missing, so your fix might actually be less hacky than it seems.

[fulmicoton]

Merging as a termporary fix, but it would be really awesome to get http2 to work eventually.