Fix RST_STREAM when stream closing

[psalin]

Fixes an issue where a RST_STREAM message is sent each time a
stream is closed. As was the case with the code prior to hpack
dynamic table concurrency fixes, sending trailers in
half_closed_remote state should transfer the state to closed with
a timeout action.

This is an alternative solution to #7 that fixes tsloughter/grpcbox#51 the way it used to be before (https://github.com/tsloughter/chatterbox/pull/5/files#diff-d3c0445427befca915a9897b50d4d356e5e360fd3bac4f0a773a4dd639771b3dR573).

[fnchooft]

Validated that the fix works.
Easiest way I found:
in grpcbox-directory:

mkdir _checkouts
cd _checkouts
git clone https://github.com/psalin/chatterbox.git
cd chatterbox && git checkout fix_rst_stream

After that clean the _build-dir and recompile.

Check deps:
rebar3 tree

I was facing the same issue using the grpcui-go-package.

[tsloughter]

I assume the 0 is to force a state timeout, but it may be better to use next_event to trigger an action to happen after.

[psalin]

The timeout 0 method is used throughout the file so maybe best to keep it in this commit for consistency and leave refactoring to use next_event to a separate task.

[tsloughter]

Yea, works for me, I guess I should merge this and make a release tomorrow.