MEDIUM: mux-h1: Don't block reads when waiting for the other side

MEDIUM: mux-h1: Don't block reads when waiting for the other side

When we are waiting for the other side to read more data, or to read the
next request, we must only stop the processing of input data and not the
data receipt. This patch don't change anything on the subscribes for
reads. So it should not change anything. The only difference is that the H1
connection will try to read data if it is woken up for an I/O event and if
it was subscribed for reads.

This patch is required to fix abortonclose option for H1 client connections.