fix(http,server): Update tests to use non-deprecated futures methods.

These seem mostly to be renames, with the exception of Unpark -> Notify.

src/http/body.rs

@@ -133,7 +133,7 @@ fn test_body_stream_concat() {
         tx.send(Ok("world".into())).wait().unwrap();
     });
 
-    let total = body.concat().wait().unwrap();
+    let total = body.concat2().wait().unwrap();
     assert_eq!(total.as_ref(), b"hello world");
 
 }