Fine-tune the Ordering for the atomic usages

[wang384670111]

SeqCst is overly restrictive. I believe that the ordering can be appropriately modified.
I think that active is merely signal for multithreading purposes and do not synchronize with other locals. Therefore, using Relaxed ordering should suffice.

jsonrpc/ws/src/metadata.rs

Line 29 in dc9550b

if self.active.load(atomic::Ordering::SeqCst) {

jsonrpc/ws/src/session.rs

Line 166 in dc9550b

self.active.store(false, atomic::Ordering::SeqCst);

jsonrpc/ws/src/session.rs

Lines 277 to 291 in dc9550b

	if !active_lock.load(atomic::Ordering::SeqCst) {
	return;
	}
	if let Some(result) = response {
	let res = out.send(result);
	match res {
	Err(error::Error::ConnectionClosed) => {
	active_lock.store(false, atomic::Ordering::SeqCst);
	}
	Err(e) => {
	warn!("Error while sending response: {:?}", e);
	}
	_ => {}
	}
	}