fix(http2): pass proper value to h2 max_local_error_reset_streams

The patch #3528 added the ability for hyper users to configure
`max_local_error_reset_streams` via the server builder to hyper
v0.14.29. It was then pulled in to hyper v1.2.0 as well in #3530, where
the wrong parameter `max_pending_accept_reset_streams` is passed to h2's
builder as `max_local_error_reset_streams`.

This could lead to significant impact especially when a hyper user does
not set `max_pending_accept_reset_streams`, because its default value is
`None` and passing `None` to h2's `max_local_error_reset_streams` method
will make the server vulnerable to DOS attacks.

This issue has been fixed in this patch, simply by passing the correct
value to the h2's builder method.

Author: magurotuna

src/proto/h2/server.rs

@@ -135,7 +135,7 @@ where
             .initial_connection_window_size(config.initial_conn_window_size)
             .max_frame_size(config.max_frame_size)
             .max_header_list_size(config.max_header_list_size)
-            .max_local_error_reset_streams(config.max_pending_accept_reset_streams)
+            .max_local_error_reset_streams(config.max_local_error_reset_streams)
             .max_send_buffer_size(config.max_send_buffer_size);
         if let Some(max) = config.max_concurrent_streams {
             builder.max_concurrent_streams(max);