Use progenitor-based client once scoped link-local v6 addresses are supported.

[rcgoodfellow]

The code that we currently use for sending requests to peer routers for prefix exchange uses hyper and manual message construction.

maghemite/ddm/src/exchange.rs

Lines 109 to 118 in 60a0858

	let uri = format!(
	"http://[{}%{}]:{}/pull",
	addr, ctx.config.if_index, ctx.config.exchange_port,
	);
	let client = hyper::Client::new();
	let req = hyper::Request::builder()
	.method(hyper::Method::GET)
	.uri(&uri)
	.body(hyper::Body::empty())
	.unwrap(); //TODO unwrap

maghemite/ddm/src/exchange.rs

Lines 165 to 178 in 60a0858

	let payload = serde_json::to_string(&update).unwrap(); //TODO unwrap
	let uri = format!(
	"http://[{}%{}]:{}/push",
	addr, config.if_index, config.exchange_port,
	);
	let client = hyper::Client::new();
	let req = hyper::Request::builder()
	.method(hyper::Method::PUT)
	.uri(&uri)
	.body(hyper::Body::from(payload))
	.unwrap(); //TODO unwrap
	let resp = client.request(req);

This is because progenitor-based clients do not currently support scoped v6 addresses.

• Support for scoped IPv6 link-local addresses. progenitor#296.

When this is addressed, we should switch to using a progenitor-based client to get more compile time safety and make things less error prone.