Event pipe: disabled c->read->available checking for SSL. In SSL connections, data can be buffered by the SSL layer, and it is wrong to avoid doing c->recv_chain() if c->read->available is 0 and c->read->pending_eof is set. And tests show that the optimization in question indeed can result in incorrect detection of premature connection close if upstream closes the connection without sending a close notify alert at the same time. Fix is to disable c->read->available optimization for SSL connections.