Reassign capacity from reset streams. (#320)

I believe this was an oversight - a stream that is reset can still have some
capacity assigned to it (e.g. if said capacity was assigned in the same poll as
the reset), which should be redistributed.

src/proto/streams/streams.rs

@@ -284,9 +284,9 @@ where
 
         let actions = &mut me.actions;
 
-        me.counts.transition(stream, |_, stream| {
+        me.counts.transition(stream, |counts, stream| {
             actions.recv.recv_reset(frame, stream);
-            actions.send.recv_reset(send_buffer, stream);
+            actions.send.recv_err(send_buffer, stream, counts);
             assert!(stream.state.is_closed());
             Ok(())
         })