BUG/MINOR: h2: try to abort closed streams as soon as possible

The purpose here is to be able to signal receipt of RST_STREAM to
streams when they start to provide a response so that the response
can be aborted ASAP. Given that RST_STREAM immediately switches the
stream to the CLOSED state, we must check for CLOSED in addition to
the existing ERROR check.

To be backported to 1.8.
1 file changed